Cognitive and Contextual Influences in Determination of Latent Fingerprint Suitability for Identification Judgments
Quantitative Measures in Support of Latent Print Comparison
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Julie Luby Nicholson*, M.F.S.; Todd W. Bille*, M.S.; Michael J. Malia*, Ph.D; Robert A.
Bever*, Ph.D.
The Sirchie® KRIMESITE Imager. is a tool that can be used to detect and document latent fingerprints on various surfaces without the use of chemical enhancement. The Imager takes advantage of the different UV light reflectance properties of the fingerprint and the surface on which it is located. Large surfaces can be searched quickly and then any fingerprints detected can be digitally photographed for comparison purposes. Due to the use of specific optic filters, the search for fingerprints can be conducted in daylight or darkness. A growing trend in forensic DNA analysis is the analysis of the epithelial cells contained within a fingerprint or fingerprint smudge that is not suitable for fingerprint comparison purposes. One concern from a DNA analysis perspective is the exposure of the limited biological material to the UV light used by the KRIMESITE Imager. which can be harmful to the DNA.
The objective of this study was to determine the effects of ultraviolet light on DNA analysis and to determine the ideal circumstances for biological fluid examination when using a shortwave ultraviolet light source.
Human buccal cells on paper were used to simulate a biological stain. The cells were exposed to a 12 Watt, shortwave (254nm) ultraviolet light for one minute, two minutes or three minutes at distances of one foot, two feet, or three feet. After exposure to the ultraviolet light, DNA was extracted from the stains for subsequent quantification and STR (Short Tandem Repeat) analysis using PowerPlex® 16 (Promega Corporation).
Results indicate that short-term (one minute) exposure of these biological samples to ultravioletlight does not greatly affect downstream DNA analysis. A longer exposure (two minutes) at a short distance (one foot) causes allelic dropout, which may be due to degradation of the biological sample. However, increasing the exposure distance to two feet or three feet improves the recovery of DNA from the paper. DNA analysis was most affected by longer exposure (three minutes) to ultraviolet light, resulting in poor recovery and increased allelic drop out.
This technique was subsequently used on probative evidence successfully. Ultimately, this information will be applied to the examination of fingerprints and a method will be developed to scan evidence for biological stains using ultraviolet light causing minimal damage to the DNA.
*The Bode Technology Group, Springfield, Virginia
RUVIS Photo of
latent Print on Soda Can
How CSIs process wet surfaces for latent fingerprints.
It had rained for more than 5 hours when an observant police patrol officer found the car believed to have been used in an armed robbery. The vehicle’s description, color and license tag all match the radio bulletin broadcast earlier during the “graveyard shift.” The vehicle had also been reported stolen the day before.
In short order, the crime scene investigation team arrives at the scene and makes a quick visual survey of the vehicle’s exterior. Of particular interest are areas that may have been touched by the previous occupants. Using flashlights held at different angles, the CSIs examine the exterior for possible latent prints. They may or may not see any. After all, latent print defined means one that is not readily visible.
Processing for latent prints throughout the vehicle’s interior will be a routine matter, but the exterior poses a particular problem—it is soaking wet, and a constant drizzle continues to fall.
Latent fingerprint developing powders are generally the first choice for investigators working crime scenes, and in this case, vehicular crime scenes. To process areas of the exterior, the crime scene technician will apply a specially formulated powder using either a fiberglass filament or animal (camel or squirrel) hair brush. But using this dry powder on a wet surface will only result in a mess—and any fingerprint ridge detail will be obliterated.
The investigators are left with just two options:
For Option 2. above, many CSI teams will employ a formulation that has become known as Small Particle Reagent or simply SPR.
Unlike many other latent print development chemicals such as Silver Nitrate and Ninhydrin, which originally had other scientific uses, SPR resulted from specific research and experimentation into finding a means of developing latent prints on wet surfaces.
The original SPR formula consisted of a very finely ground black powder—Molybdenum disulfide, along with a liquid detergent and water. This mixture, when sprayed on a vertical or near-vertical surface, tends to run downward. If latent prints are present, the liquid-suspended black powder will attach itself to the moisture residue of latent prints, thus making the ridge structure of the print plainly visible.
SPR Dark works fine on light colored surfaces but is of little value if the surface is painted black. What researchers came up with next was a formula using finely milled white powder—Titanium dioxide—and the same water-detergent mixture. SPR Light and SPR Dark are found in many crime scene investigation kits.
In recent years, a third formula was developed that will aid in latent print recovery from multicolored backgrounds. This mixture is fluorescent—it glows in the dark when longwave UV light is applied. Like its counterparts, SPR UV employs the same detergent-water carrier.
SPR UV then fills an apparent void in formulations providing the CSI with enough variety to cover most wet surface conditions.
Application of a SPR formula is simple-it is applied using a spray bottle. The mixture is sprayed onto the surface above the area suspected of containing latent prints, and it is allowed to run down across the surface. The solution also lends itself to tray development.
While its primary purpose is latent print recovery on wet surfaces, it may be used on virtually non-porous surface—wet or dry.
Once latent prints are developed, they must be immediately photographed, as they are quite fragile and when wet, they may be very difficult to lift using tape, hinge-lifters, etc.
Resourcefulness resulted in the discovery of SPR. Researchers saw a need and took the logical steps to meet it. To learn more about how forensic science uses existing processes as well as inventing new ones in the war against crime, please visit the many other sections in this blog. Use the navigation window to the right labeled Categories.
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A single crime scene will offer a variety of surfaces that potentially harbor latent fingerprints—some present little difficulty in developing and lifting these prints while others offer significant challenges. One surface that comes to mind are textured surfaces such as leather furniture, handbags, wallets, certain counter and desk tops, and automobile interiors.
A second type of difficult surface involves materials such as plastic baggies, cellophane packaging, shrink-wrap, “Saran” wrap and aluminum foil. These materials are favorites of the drug trade and they provide convenient, easy to handle, economical storage and transfer packaging. But their extreme flexibility often presents problems.
No major difficulty is encountered when developing any latents present on textured surfaces. But preserving the latent is often a challenge. Many CSIs report that magnetic latent powder provides the most consistent results when processing non-ferrous, rough surfaces. The biggest advantage with using a magnetic powder is that the powder itself forms the brush so there is no need to use an animal hair or fiberglass brush on delicate surfaces like crumpled cellophane or aluminum foil.
The following steps are used by many skilled CSIs who report excellent results:
1. Carefully flatten the material to be dusted onto a flat, smooth surface. It may be necessary to use a small length of tape to hold one end stationary.
2. Measure out a small amount of the magnetic powder to be used onto a clean sheet of paper (this is to avoid contaminating the powder supply with foreign material like dust, dirt, grease, etc. from the surface being processed). Use a powder that offers good photographic contrast against the substrate.
3. Pickup the powder with the magnetic wand and apply the powder to the surface.
Once latents appear they should be photographed before proceeding. Be Certain to Include a Scale in All Photos.
Lifting prints from the above mentioned surfaces will be the most difficult part of this process, since lifting tapes, hinge lifters, etc., will most likely stick to the surface and removal will most certainly damage some materials. Another reason to avoid this type of lifting procedure is consideration of the textured or roughness of the material.
The preferred method, one that will not damage the material holding the latent, is to employ any of several silicone materials. Among the most popular methods are Mikrosil and Liquid Silicone Rubber.
Mikrosil is silicone putty available in several different colors. It has the consistency of toothpaste. If a black or gray powder produced the latents, use white Mikrosil. This material is also available in gray, brown and black.
Mikrosil is a two-part formulation: One tube contains the base material and a much smaller tube contains a blue-colored catalyst. Mikrosil, like most silicone products, requires a catalyst to make it harden or “set up.”.
Follow the manufacturer’s instructions when mixing the base and catalyst. Mixing time must be kept to a minimum as the material begins to setup in 20-30 seconds. Stir vigorously until the color of the blue catalyst is no longer visible in the base material, and then apply it to the latent print to be lifted. Setup time is about 10-15 minutes.
Download a copy of the Mikrosil Technical Information Bulletin Here
Liquid Silicone Rubber is a viscous liquid supplied in jars. It has the consistency of thick maple syrup. It too requires the use of a catalyst. To use this substance, stir the contents of the jar well as some settling may have occurred. Pour the quantity needed to cover the area with latent prints into a suitable mixing container and add liquid catalyst according to instructions. After mixing for at least one minute, pour the mixture onto the surface, and allow 20-30 minutes for setup.
Once either casting material is cured, merely lift the cast from the surface, Photograph the lift with a scale.
Download a copy of the Technical Information Bulletin for No. 634C Liquid Silicone Rubber Here
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Complied by Don Penven
Terrorist Bombing in Madrid
In March 11, 2004, terrorists bombed several trains in Madrid, Spain, killing 191 people and injuring more than 1,800. A few days later the Spanish police sent a latent fingerprint electronically to the FBI’s Latent Print Unit (LPU).
The LPU identified the latent print from Madrid as belonging to an Oregon resident, whose home and office were searched and his computer and files were seized. He was arrested and imprisoned for 15 days in May 2004. He was released after the fingerprints were matched to an Algerian man.
This entire affair cast serious doubt upon the FBI’s ability to affect a positive fingerprint identification,
What is a Daubert Hearing?
Quite often, fingerprint identifications are challenged in court—despite the fact that fingerprints have been the primary means of identification for the past 100 years. When such challenges are made by defense attorneys, the trial judge will often schedule a “Daubert Hearing.”
A Daubert hearing is, in effect, a mini-trial within a trial, conducted before the judge without the jury present, over the validity and admissibility of expert opinion testimony. This requires the judge to be certain that the expert's testimony is relevant to the matter at hand and that it is positioned on a reliable foundation.
A conclusion will qualify as scientific knowledge if the expert can demonstrate that the evidence results from sound "scientific methodology" and is derived from the scientific method.
According to Wikipedia, the Supreme Court defined "scientific methodology" as the process of formulating hypotheses and then conducting experiments to prove or falsify the hypothesis, and provided a nondispositive, nonexclusive, "flexible" test for establishing its "validity":
1. Empirical testing: the theory or technique must be falsifiable, refutable, and testable.
2. Subjected to peer review and publication
3. Known or potential error rate.
4. The existence and maintenance of standards and controls concerning its operation.5. Degree to which the theory and technique is generally accepted by a relevant scientific community.
How Latent Examiners use ACE-V to ensure accurate identifications
ACE-V is an acronym for Analysis, Comparison, Evaluation and Verification:
Analysis: The first step is analysis. Analysis is a thorough examination of the latent print. The latent print would be examined to determine the ridge formations that exist at three levels of detail. Level 1 detail refers to the first appearance of the print noticed at the beginning of an examination. Generally, “Level 1” refers to the overall pattern or ridge flow tendencies of the print. Level 2 detail refers to the next features observed, generally those with a physical dimension on the order of magnitude of a ridge width. The so--called “Minutiae” or “points,” are level 2 details. Level 3 detail refers to smaller features generally observed under magnification. Level 3 features are normally contained within a single ridge, such as shapes and positions of sweat pores (poroscopy) or distinctive shapes on the edge of a ridge (edgeoscopy). Incipient ridge (ridges that never fully developed) shapes are also usually considered level 3 details, but the presence of incipient ridges in general would be a level 1 consideration.
Comparison: During the comparison phase the examiner concentrates primarily on the known, or inked, prints. The examiner searches each inked print in turn, observing all three levels of detail in a search for an image that is consistent with the detail found in the latent print during its analysis, and that has the target selected for the search.
Evaluation: In this phase, the two prints are examined together, side by side. The examiner finds features first in the unknown print, then in the known print, and then evaluates the corresponding features to determine if they are within tolerance for the level of clarity that exists in the images. In this manner, the examiner goes back and forth between the two prints, finding features first in the unknown, and then evaluating their appearance in the known print.
Verification: The general rule is that all positive identification opinions must be verified by a second qualified expert. The second expert may repeat the entire process, but the comparison may not be blind. That is, the second expert may know from the outset that another examiner has already made the positive identification.
For more information on fingerprint science, you may download the free training manual, Latent Fingerprints, From Crime Scene to Courtroom
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In the late 1970s, members of the US Army CID Lab in Japan brought home a novel method for developing latent prints. The forensic scientists in the Tokyo National Crime Lab had discovered that the fumes from cyanoacrylate adhesives (CA) or superglue, reacted with the moisture of latent fingerprints in such a way that a latent print on a non-porous surface was covered with a hard coating that encased the delicate ridge structure of the latent print.
Today, at least here in the U.S., superglue fuming is a basic step in the crime-solving playbook for a majority of crime labs. Back in the early days of superglue research, fuming chambers ranged from large plastic bags to converted fish tanks. Many new, more functional appliances are now available.
The pros and cons of employing superglue fuming are many: On the PRO side—it protects fragile latent prints by resisting accidental bumps and scuffs that would damage the ridges, it encapsulates the moisture content of a latent thus preventing vaporization and it is a means of processing large quantities of evidence at one time in all shapes and sizes.
On the CON side; superglue fuming produces white latent prints that often require the addition of a contrasting color to enable better viewing and photography of the latents, and it leaves a white residue on many of the surfaces the fumes contact. Although some early literature indicated that the fumes may be toxic, this theory has been disproven. The fumes are noxious but not dangerous.
Over the years many innovative advances have grown out of basic research employing superglue. Among some of the best ideas is vacuum fuming. Researchers discovered that superglue is a top performer when evidence and a few drops of superglue are sealed into a vacuum chamber. Current users of the vacuum fuming method report that is possible to fill a chamber with numerous articles, including evidence such as large plastic trash bags, and cramming in all that will fit seems to have little or no effect on getting excellent results.
During the first few years of superglue experimentation, researchers sought a means of accelerating the development. Faster is better—right? Not necessarily. One of the first acceleration methods was impregnating cotton pads with a sodium hydroxide solution. This did indeed produces near instant clouds of white smoke. But over time such use fell into disfavor due to health-related concerns.
Two of today’s most popular methods for superglue acceleration are:
1. Apply superglue to untreated cotton pads. This is quite safe and provides much faster fuming than just placing a few drops of glue inside a fuming chamber.
2. The application of heat is quite effective in speeding up the development process. This is accomplished by using a small coffee warmer. More sophisticated fuming chambers have built-in heaters.
A number of crime labs are encouraging crime scene investigators to fume fragile evidence prior to packaging for transmittal to the crime lab. This step has probably saved countless numbers of latent prints from being accidently destroyed during shipment to the crime lab.
Cyanoacrylate fuming is the number one choice as a first step in locating latent prints on non-porous surfaces. Until something better comes along, the crime scene technician should consider adding this process to the crime scene equipment kit—if this hasn’t been done already.
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Reprinted from ScienceDaily: http://www.sciencedaily.com/releases/2010/05/100511102121.htm
CSI notwithstanding, forensics experts cannot always retrieve fingerprints from objects, but a conformal coating process developed by Penn State professors can reveal hard-to-develop fingerprints on nonporous surfaces without altering the chemistry of the print.
"As prints dry or age, the common techniques used to develop latent fingerprints, such as dusting or cyanoacrylate -- Superglue -- fuming often fail," said Robert Shaler, professor of biochemistry and molecular biology and director of Penn State's forensic sciences program.
This happens because most of the techniques currently used for developing fingerprints rely on the chemistry of the print. Fingerprints are made up of a mixture of secretions from the body that reacts with different chemicals to form a visible or fluorescent product. Infrared and x-ray imaging also target specific chemicals left behind by the ridges and valleys in the skin.
"Lots and lots of processes take advantage of the chemistry of fingerprints," said Shaler. "This approach looks at the geometry of the fingerprints."
The conformal coating applications suggested by Shaler and Ahklesh Lakhtakia, Charles Godfrey Binder Professor in engineering science and mechanics, use the physical properties of the fingerprint, not the chemistry of the substances left behind. In fact, the researchers believe that even after the fingerprints are developed using the coating, forensics experts could sample the fingerprint material to determine specifics about the person who left the prints.
"The body chemistry of the person who left the fingerprint can tell us some things," said Shaler. "If the suspect is older or younger or a lactating mother, for example."
The researchers used a form of physical vapor deposition -- a method that uses a vacuum and allows vaporized materials to condense on a surface creating a thin film. Normally, the deposition process requires exceptionally clean surfaces because any speck of dust or grease on the coated surface shows up as a deformity. However, with fingerprints, the point is to have the surface material's ridges and valleys -- topography -- show up on the new surface so analysts can read them using an optical device without the necessity of chemical development or microscopy.
"This approach allows us to look at the topography better and to look at the chemistry later," said Shaler. "We wouldn't have thought of this by ourselves, but we could do it together."
One benefit of this approach would be the ability to retrieve fingerprints off fragments from incendiary or explosive devices and still be able to analyze the chemicals used in the device.
The specific method used is a conformal-evaporated-film-by-rotation technique developed to create highly accurate copies of biological templates such as insect eyes or butterfly wings. Both are surfaces that have nanoscale variations.
"It is a very simple process," said Lakhtakia. "And fingerprints are not nanoscale objects, so the conformal coating is applied to something big by nanotechnology standards."
The researchers tested two materials for coating, magnesium fluoride and chalcogenide glass -- a combination of germanium, antimony and selenium. The coating material is heated in a vacuum, while the artifact to be coated is rotated fairly quickly to allow deposition over the entire surface.
"We need to have a coating that is uniform as far as we can see," said Lakhtakia. "But we do not need much of a coating -- in the range of only a micron."
The researchers tried coating a variety of fingerprints on glass and even on tape. They coated pristine fingerprints and those that had been fumed with SuperGlue. In all cases, the coated fingerprints were usable.
Of course, like all approaches, this one can only be used on non-porous surfaces, surfaces that do not de-gas. The equipment used to deposit the coating is a laboratory device, but it can produce the coating in about 15 minutes. The researchers would like to design a portable device that could be brought to a crime scene and produce readable fingerprints on site.
"We are in the process of redesigning the chamber and looking not just at fingerprints, but at other objects," said Lakhtakia. "These would include bullets, cartridges, footprints, bite marks and lip impressions." Shaler and Lakhtakia have filed a provisional patent application on this application.
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The following was extracted from an article published on www.clpex.com
Written & Compiled By: Thomas J. Ferriola
Identification Technician
Sebastian Police Department, Florida
Level One ( Ridge Flow & Class Characteristics) is the largest scale of information, such as the general type of the central area of the fingerprint, such as an arch, whorl, or loop. Other level one details may include such matters as the overall ridge count, focal areas of the print, such as "delta regions" (roughly triangular shaped areas where ridges flowing in different directions meet), and the orientation of the print. Showing that level one details are identical is not enough to make an identification of the finger that is the source of a latent print.
Level Two (Ridge Characteristics or Points) detail focuses on the characteristics of ridge paths, such as places where ridges bifurcate or end or create dots or islands. These features provide a great deal of detail. Each feature can be identified in terms of the type of feature (end, bifurcation, etc.), its direction, and its location with respect to other identifiable features in the print. Level two detail can be used to identify one individual finger from among the entire human population as the source of the latent print.
Level Three ( Ridge Structure ) detail can be described as "ridge detail," with such tiny features as pores on a ridge and the width and shape of the ridge itself and its edges. These level three details are the most vulnerable to problems with the quality of the latent print. They are so small that a clear, high quality image is needed to make accurate comparisons. When the latent print is sufficiently clear, level three detail can contribute to the identification of the source of a latent print.
The Justice Department, FBI uses and has adopted a standard method a fingerprint examiner goes through. It is a four-step process with the acronym "ACE-V," for analysis, comparison, evaluation, and verification, and focusing on Level one, Level two and Level three details The first phase is analysis. Analysis is a thorough examination of the unknown. In the case of fingerprints, the latent print would be examined to determine the ridge formations that exist at three levels of detail. “Level one detail” refers to the first appearance of the print noticed at the beginning of an examination. Generally, “Level one” refers to the overall pattern or ridge flow tendencies of the print. “Level two detail” refers to the next features observed, generally those with a physical dimension on the order of magnitude of a ridge width. The so--called “Minutiae” or “points,” are level two detail. “Level three detail” refers to smaller features generally observed under magnification. Level three features are normally contained within a single ridge, such as shapes and positions of sweat pores (poroscopy) or distinctive shapes on the edge of a ridge (edgeoscopy). Incipient ridge shapes are also usually considered level three details, but the presence of incipient ridges in general would be a level one consideration. A large scar might be considered as level one detail, whereas a small scar might only be observed at level two. Within a scar there may be valuable level three detail. A thorough analysis of the unknown consists of far more than simply looking at the minutiae points.
Another part of the analysis of a latent print is the assessment of all of the various causes of distortion and their effect upon the print. Distortion could result from a number of sources, including the matrix, or residue, which comprises the print; the substrate, or surface, on which the print was left; the direction of touch; the pressure of the touch; reaction of the matrix with the development medium; and so on. All of these factors should be assessed during the analysis of the latent print.
Analysis also takes into consideration the clarity of the print. Clarity differences result from distortion. A latent print lacking level three detail as a result of pressure distortion, for example, might be described as having a low degree of clarity, whereas a print showing good pore and edge structure and having minimal distortion might be characterized as having a high degree of clarity.
Inherent in the analysis of the latent print is the selection of a suitable target to be memorized and used when searching the inked prints. Such a target is usually an easily recognizable cluster of minutiae points. On the other hand, it might be a distinctive scar, a prominent crease or wrinkle pattern, or any other significant and easily recognizable formation that results from features in the area of friction skin that left the print. The target will be the starting point for the second and third phases of the identification process, therefore it should be both an easily recognizable feature in the unknown print and potentially the easiest to find in the known prints.
A thorough analysis should be accompanied by the taking of detailed notes describing the latent print. Notes should make reference to all observed distortion factors. Notes may also include reference to the level of clarity present in the print. One might actually draw the target, both as an aid in its memorization and as a part of the description of the latent. On occasion, one may even choose to physically follow or trace the ridges completely throughout the print and draw a representation of the entire latent in the notes. This type of demonstrable analysis lends credence to any subsequent identification.
Once a thorough analysis of the latent print has been completed, the second phase of the identification process is comparison. Whereas, during analysis the examiner focuses exclusively on the unknown print, during the comparison phase the examiner concentrates primarily on the known, or inked, prints. The examiner searches each inked print in turn, observing all three levels of detail in a search for an image that is consistent with the detail found in the latent print during its analysis, and that has the target selected for the search.
Once a known print is located that is consistent in appearance with the unknown and contains the target, the examiner enters the third phase of the identification process, evaluation. In this phase, the two prints are examined together, side by side. The examiner finds features first in the unknown print, then in the known print, then evaluates the corresponding features to determine if they are within tolerance for the level of clarity that exists in the images. In this manner, the examiner goes back and forth between the two prints, finding features first in the unknown, then evaluating their appearance in the known print.
The reason for working from the unknown image to the known has its foundation in human psychology. When dealing with a less clear image, usually the latent or unknown print, the brain is subject to influence by “mind--set.” If a feature is first observed in a clear image, the brain may form an expectation and be tricked into “seeing” the same feature in an unclear image even though it does not actually exist there. Take, for example, in the case of a faint ninhydrin print ( a chemical used in latent print development ) in which the ridges appear primarily as a series of light dots. If the examiner concentrates on first finding points in a clear, high contrast inked print, then tries to find the same points in the poorly defined latent, mind--set might easily lead the examiner to “see” points that do not exist. To avoid this possibility, a cautious examiner always finds the features in the unknown print first, free from mind--set, then locates and evaluates the corresponding features in the known print.
During the evaluation phase of the identification process, the examiner must consider all of the differences in appearance between the two images. It is an accepted tenant of fingerprint science that no two prints will ever be exactly the same in all respects. First, any touch is a contact between a complex curved surface (the skin) and, usually, a flat surface.
This touch must necessarily be accompanied by distortion of the skin itself. Second, the amount and type of matrix (residue left behind) will differ. Third, the angle and pressure of the contact will change from one touch to the next. Fourth, the size of the area of skin coming into contact with the surface will vary. Any number of other factors may also contribute to differences, some subtle and some extreme, in the appearance of two prints that result from two touches by the same region of friction skin. It is not sufficient to look only for similarities and ignore the differences, nor is it proper to look at only some features and ignore others. The true expert must consider everything appearing in each image.
It is at this point that tolerance enters the equation. Based on an understanding of distortion and its sources, some differences in appearance fall within acceptable limits of tolerance. For example, it is an easy task to understand and to account for the differences in appearance between a print resulting from a light touch and a print resulting from a heavy touch. The differences in appearance between a fully rolled inked print and a crime scene mark are also easy to understand and easy to account for. These differences would be said to be within tolerance.
On the other hand, for example, a clear crime scene mark with a whorl pattern having an outer tracing, when compared to an inked print having a whorl pattern with an inner tracing, would be considered out of tolerance, even at level one. A ridge ending or bifurcation in one print where an open field of ridges exists in the other print would be out of tolerance at level two. Two bifurcations opening in the same direction, whose shoulders are essentially even in a crime scene mark with high clarity, would also be out of tolerance when evaluated with two bifurcations opening in the same direction in the inked print in which the shoulders were offset.
Analysis, comparison, and evaluation – ACE – takes into consideration much more than simply looking at the points in a crime scene mark, checking the inked print, and counting until a threshold number is reached. It is the evaluation, that is, the determination that all features are within tolerance as determined by the clarity of the two images, that sets the scientific process apart from the simpler idea of counting points. For that reason, this methodology is sometimes referred to as the “evaluative process.”
The final step in the process is verification the general rule is that all positive identification opinions must be verified by a second qualified expert. The second expert may repeat the entire process, but the comparison may not be blind. That is, the second expert may know from the outset that another examiner has already made the positive identification.
Some organizations do not tell the latent print examiner conducting the verification the results of their examination.
Technically speaking, verification is not a part of the identification process. The identification itself takes place in the mind of the examiner making the comparison. Verification is the identification process repeated in someone else's mind.
Independent verification, however, is a crucial part of the scientific process. Without such verification, identification has not been proven to the level required by science. No report should be made of an identification until a second qualified expert has made that verification independently of influence or pressure from any source.
Of course, the most important practical reason for having verification performed is that it reduces the risk of an erroneous identification being reported. In any field of human endeavor, there exists the potential for human error. When an erroneous identification is formally reported, almost certainly an innocent person will suffer. A conscientious program of independent verification, followed without exception, should catch erroneous identifications and prevent them from being acted upon.
Erroneous identifications among cautious, competent examiners, thankfully, are exceedingly rare; some might say, “impossible.” Clerical errors, however, are not uncommon. Writing down the wrong finger, or worse, writing down the wrong name, occurs far more frequently than a true erroneous identification.
If the most important practical function of verification is to prevent the reporting of erroneous identifications, the more frequent benefit of verification is the avoidance of embarrassment, or worse, false arrest resulting from clerical errors. A true clerical error should not be considered an erroneous identification, but department policies and procedures should be written to ensure the prevention of clerical errors.
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Download a copy of the training manual: Latent Prints From Crime Scene to Courtroom
By: Don Penven, Technical Support group
Review from Part 1 of this series:
The three contemporary methods used to develop latent fingerprints are:
1. A latent fingerprint is one that is generally not visible unless it is treated in some manner. The print itself is composed of moisture—mostly water—but it also contains small amounts of the constituents of perspiration (sweat), like amino acids, lactic acids, creatinine, choline, sugars and uric acid.
2. The palms of the hands and soles of the feet are covered with friction ridges, and these ridges have sweat pores along their surface. Sweat from these two areas has one single kind of sweat glands: Eccrine glands. Only water and the substances listed above are exuded from these glands.
Portable Fuming Chamber
3. Other parts of the body have two other sweat glands: Sebaceous and Apocrine glands. Sebaceous glands exude fatty acids, glycerides and hydrocarbons. In other words these secretions are oily in nature. Sebaceous glands are associated with hair follicles. The Apocrine glands secret water along with ions of sodium, potassium, and iron as well as proteins, carbohydrates and cholesterol.
4. When the hands come into contact with the face and hair they become contaminated with this mix.
Iodine Fuming: Iodine crystals have a unique characteristic—when exposed to air above room temperature they begin a process known to scientists as sublimation. This process is when a solid like iodine crystals converts directly into a gas—iodine fumes. All it takes is a little heat to accelerate the sublimation process.
Iodine fuming is a process used to develop latent fingerprints on porous surfaces such as paper, cardboard and raw wood. Criminalists and crime scene investigators have found this to be a valuable tool for developing latent prints at the crime scene or the crime lab. But iodine fuming has a few shortcomings.
The iodine method of latent print development is generally the first step in the attempts to develop latent prints that are thought to be reasonably fresh. The advantage of this method is that it is non-destructive to subsequent testing using other chemicals.
Iodine fuming requires no sophisticated apparatus in order to deliver its fumes onto a porous surface. Iodine fumes react to the sebaceous sweat secretions (oil) that contaminate the fingertips. Touch your nose, cheek, ears, arms and chest and you have these secretions on your fingers.
The iodine fumes develop latent prints that are orange to brown in color. This process works best on prints that are known to be fresh; like a ransom note, a holdup note handed to a bank teller or even a suicide note.
But as mentioned, iodine fuming has its shortcomings—mainly that the prints that do appear are fugitive—they begin to fade shortly after development; and iodine fuming only works on prints that are thought to be reasonably fresh. You will hear more on this in a moment.
The fuming procedure is relatively simple:
1. Iodine crystals are placed in a confined area along with a document or other porous items. At the crime scene this can be a zip-top plastic bag. In the crime lab it can be a converted fish tank, or a fuming chamber specifically built for this purpose.
2. A low level heat source is used to begin the sublimation process. This can be simply your hand wrapped around the zip-top plastic bag containing iodine crystals or an inexpensive coffee warmer.
3. The iodine fumes are usually visible—a kind of purple haze. Once the fumes are seen, the heat source may be removed. Prints will be visible in seconds.
4. The next step is to remove the evidence being processed, and then photograph any visible latent prints. Be certain to include a scale that is visible in each shot. If the prints are reasonably fresh, they should remain visible for 15-20 minutes or longer.
5. Once photographs are completed, you may apply an iodine enhancer/fixative to the developed prints, which provides a permanent image.
Cyanoacrylate Fuming:
Back in the late 1970s members of the US Army Crime Laboratory in Japan were shown an interesting method for developing latent fingerprints on non-porous surfaces such as metal, painted wood, plastic and glass. Instead of using powders, members of the Japanese National Police Force used a material called cyanoacrylate to develop latent prints on most nonporous surfaces.
At that period of time this material was popularly known as Super Glue. The name Super Glue was once trademarked, but through common usage, the term superglue has become generic and several cyanoacrylate manufacturers use it to describe their product.
If you have ever used it, you know that cyanoacrylate has a very strong, noxious odor. You may have seen commercials long ago showing how a drop of this glue could bond an automobile to the hook on a crane, which lifted it off the ground. In any case, the glue does form a tight bond—provided there is a very thin film of moisture (water) on both surfaces to be bonded. And of course most surfaces on this planet have moisture on them as a result of humidity.
So how can this develop latent prints? It is really very simple. A process known as chemical “fuming” is used. The crime lab technicians will carefully place several items of evidence into an enclosure. Early fuming tanks were nothing more than fish tanks with a cover of some sort.
Several drops of glue are measured out into a fuming tray (usually an aluminum cup-like object). This is placed in the chamber and the chamber is sealed up. Development without any sort of acceleration takes several hours, but a small coffee warmer can be used under the glue to accelerate the process.
It is also possible to accelerate the fuming process by adding a few drops of the glue onto a cotton pad. To protect the surface of the floor in the fuming chamber, place the cotton pad on a piece of aluminum foil or one of the cups mentioned above. This is one very good reason for NOT wearing cotton gloves. Considerable heat is generated during the fuming process and may cause burns to the hands.
The glue fumes will circulate inside the chamber and will come in contact with the various items of evidence. The fumes will polymerize (turn into a solid) on any moisture on the objects—like fingerprint residue!
The resulting developed latent prints will be hard as a rock, and will conform to the ridge structure that the suspect left behind. The developed prints are white in color so visual and photographic contrast may be added on light colored surfaces using fingerprint powders or dye stains.
Many crime labs suggest that CSIs fume evidence with cyanoacrylate to prevent damage or loss of the latents during transport to the lab.
If you would like to learn more about crime scene investigative techniques, an abundance of information is available from this website.
You may download a free training manual, Overview of Latent Development Techniques
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References:
Lee Lofland, The Grave yard Shift-“”Ninhydrin and Iodine Fuming;” http://www.leelofland.com/wordpress/?p=259, April 11, 2011
German, Edward, CLPE, FFS, Cyanoacrylate (Superglue) Fuming Tips, <www.onin.com>: April 11, 2011
By: Don Penven, Technical Support Group
Adhesive Side Powder
Over time, many products have evolved that provide a method of fixing something, and the same is true for the tools used by crime scene investigators.
You have probably heard the old saying, “If it is supposed to move and doesn’t—use WD-40. If it moves and shouldn’t—use duct tape.” These two products have “fixed” a great many problems but one in particular—duct tape—created a whole new problem.
The criminal element has used duct tape to its advantage—it fixes something that moves—mainly the thing that moves is a hapless victim of an armed robbery, sexual assault or kidnapping. Duct tape is used to bind the victims—arms and legs—and it is used across their mouths to silence them.
Most brands of duct tape have a smooth, non-adhesive side, and this surface is relatively easy for a CSI to develop latent prints using conventional latent fingerprint powders. But, would you believe that the adhesive-side of most tapes with a tacky surface can yield better latent prints than the smooth, outer side?
For a number of years now, CSIs and crime laboratory technicians have been getting extremely useful latent prints from the adhesive-side of duct tape, packing tapes (transparent and opaque), surgical tape—virtually any tape equipped with a soft, non-drying adhesive.
But the development technique is not always a simple matter of just applying a developer of some sort. In many cases the tape is stuck to itself or mangled as it is removed from the victim. In some cases, the tape is wound on a tool or weapon in several layers also making removal difficult.
Most of the manufacturers of police field kits that provide the necessary tools to recover latent prints from the adhesive-side also include a chemical that breaks the stickiness—allowing the tape to be straightened out.
Laboratory experimentation led to the development of adhesive side development techniques. Currently two methods are available to treat the adhesive-side of most tapes equipped with non-drying adhesives:
Adhesive-side powders are used as follows:
1. Using the powder/surfactant combination premixed by the investigator, or using the factory mixed solution, apply the powder mixture directly to the adhesive-side of the tape using a soft bristle brush or a cotton “dauber.”
2. Allow the mixture to stand for just 10-15 seconds, and then immediately wash off the excess reagent.
If the perpetrator did come into contact with the adhesive side of the tape, which is highly likely, then the likelihood of his prints being visible is highly probable!
Once the processed tape is dry, the developed prints may be photographed (with a scale) and covered with a protective layer of regular fingerprint lifting tape.
Since research on this technique is incomplete, we are not absolutely certain as to what these reagents are acting upon:
1. It could be that the reagent is adhering to the usual, oily residue deposited by the fingertips, or…
2. It could be a thin layer of dead skin from the fingers that the adhesive pulled off, or..
3. It could be a combination of both kinds of residue.
Regardless of the why it works…the fact is that it does work, very well indeed!
Want to learn more about the exciting career of crime scene investigation…Then down load this Training Manual, “The Evidence Collection Mission.”
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By: Don Penven, Technical Support group
A number of special methods for development of latent fingerprints have evolved over the years. While it is not a frequent occurrence, sometimes the surface to be dusted with latent print powders is damp or wet as a result of heavy dew or precipitation.
Small Particle Reagent (SPR) was developed to handle a situation where a wet surface is encountered. SPR is formulated from finely ground chemical particles such as molybdenum disulfide or titanium dioxide mixed with a surfactant and water. A third reagent is a mixture of a fluorescent powder (that may be seen when exposed to ultraviolet (black) light, a surfactant and water.
As is the case when applying latent fingerprint development powders, either the white titanium dioxide or charcoal gray (molybdenum sulfide) is used to get the best photographic contrast. The ultraviolet reagent is indicated for use on multicolored backgrounds.
Small particle reagents are usually supplied in manual pump spray bottles. The spray is directed toward the area with the best potential for locating latent prints. On vertical surfaces the reagent is sprayed directly above the area being tested, and it is allowed to run down over this area. The reagent may also be used for tray development.
When latent prints develop—due to the reagent particles clinging to any oily fingerprint residue present—a light spray of clean water is directed toward the developed prints to wash away any excess reagent. The latents are then photographed with a scale, and then they may be “lifted” after drying.
An important feature of using Small Particle Reagent is the fact that cleanup after the prints are photographed and lifted is a matter of just wiping the surface clean with a rag or cloth. Fingerprint development powders are typically difficult to remove from many surfaces so Small Particle Reagent is an excellent alternative for outdoor use.
Want to learn more about the exciting career of crime scene investigation…Then download this Training Manual, “The Evidence Collection Mission.”
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References:
Crime and Clues, “Small Particle Reagent,” <http://www.crimeandclues.com/spr.htm>, April 6, 2009
Lee, Dr. Henry C. and R.E. Gaensslen ed. Advances in Fingerprint Technology, New York: Elsevier Science Publishing Co.; 1991.
RUVIS: A Device That Allows CSIs to “See” Latent Prints Before Development
The Reflected Ultraviolet Imaging System (RUVIS) was first made available to law enforcement agencies more than a decade ago and is now in use throughout the U.S.A. by Federal, state and municipal agencies, and it has become a valuable aid to governments around the world.
RUVIS derives its uniqueness from the fact that this handheld device permits investigators to actually see latent fingerprints on nonporous surfaces BEFORE any attempt is made to develop them using the traditional methods discussed in previous articles in this series.
The basic theory behind RUVIS is the fact that certain surfaces reflect Shortwave Ultraviolet light, which in itself is invisible. But a RUVIS device changes this.
RUVIS is a two-part system consisting of a portable shortwave UV light and the handheld RUVIS device.
Here’s the basic theory of RUVIS operation:
1. Most nonporous surfaces will either reflect UV light or will absorb it so that no light is reflected. Much depends on the angle that the UV light strikes the surface.
2. The RUVIS device utilizes a specially-constructed lens designed to pass UV light. Most commercially- made camera lenses have features that block UV light, because it interferes with the color balance of the resultant photographs.
3. The RUVIS device is equipped with a “bandpass filter” located behind the lens assembly that blocks all but shortwave UV light—including ambient light in the scene. This permits use in bright sunlight or total darkness. Only the reflected UV light passes through electronic circuitry that amplifies the weak UV light and converts it to visible light—so that it can be seen.
4. Depending on the color and physical nature of the surface being examined, and the angle and distance from the surface that the UV light is positioned, either the background or the moisture of a latent print is seen through the RUVIS device.
5. In the case where the surface is reflecting the light, any latent prints on this surface will absorb the light. The result is that the background will appear as a lighter color on the RUVIS viewing screen while the ridge structure of the latent prints will appear dark in color.
6. A slight change in position will sometimes cause the opposite to occur: the background will be dark and the ridges will be light in color.
Some RUVIS devices permit the direct connection of a camera to the viewer permitting photos of the latent prints to be taken before any attempt is made to develop and lift these prints.
Using a RUVIS device has many benefits both at the crime scene and in the crime lab. Since the user can actually see what is present, he can eliminate the time taken to develop smudges and smears, which have no apparent value. The RUVIS operator can direct his attention to only those prints that may have forensic value.
But another advantage is that recent discoveries make it possible to recover DNA evidence from latent prints, so those CSIs who are collecting DNA evidence can be directed to the smudges and smears instead of collecting useable latents.
Overall, RUVIS saves considerable time that is usually spent in processing an entire crime scene for latent prints.
RUVIS technology is just one example of how law enforcement and private industry have partnered in the war against crime. For more information on this remarkable instrument you are invited to download a FREE CATALOG that covers RUVIS more fully. Click HERE! This catalog may be downloaded by individual sections and RUVIS is found in the third catalog section. You may also download a free copy of: “Overview of latent Print Development Techniques.”
Watch RUVIS locate latent prints without powders or chemicals
Having a problem seeing the video? Watch it on YouTube HERE
Don Penven is a freelance writer and photographer based in Raleigh, NC. He has over 30 years of direct and indirect experience in law enforcement and crime scene investigation.
FBI Latent Print Hit of 2009
Part 2 of this series discussed the use of latent print development powders. This article will cover some of the most popular methods of chemical treatments.
Latent print powders are of little use on porous surfaces such as paper, cardboard and raw wood; the reason being that a latent print is over 90% water, which is absorbed and dispersed in the surface. However, if prints are known to be fresh, regular black powder and magnetic powders may produce good results, and use of powders will not interfere with chemical processing. Crime scene investigators (CSIs) are able to recover latent prints from porous surfaces without a great deal of difficulty using chemical methods.
In Part 1 of this series you learned that a latent print is a combination of substances that make up human perspiration (sweat). The sweat pores exude substances like water, amino acid, carbohydrates, choline, proteins and uric acid. The fingertips also deposit oils from contact with areas of the body that harbor sebaceous glands—like on the face, arms and chest.
When examining porous objects like those listed above, the CSI or laboratory technician will follow a specific regimen of tests. Usually the first test is iodine fuming, which we will discuss in a subsequent lesson. Iodine fumes are used first as they are non-destructive to the testing that will follow. But iodine fumes are highly toxic and special care must be exercised when using iodine fuming techniques.
Special Note! All items that are transportable should be taken to the crime lab for processing.
Several chemical reagents are used in many crime labs as they are very sensitive and often produce spectacular results. Let’s take a look at the processing sequence recommended by the FBI and the British Home office. The best order of processing is: Iodine Fuming, DFO, Ninhydrin, and then either Silver Nitrate or Physical Developer. If Ninhydrin is used prior to DFO, the DFO prints will not fluoresce.
Note that DFO and Ninhydrin are a biological stains, and when they react with an amino acid, they exhibit a visible color. Amino acids are a component of sweat and oddly enough they do not disperse into the surface. In fact amino acids form a permanent bond with the cellulose structure of paper, cardboard and raw wood. And this bond conforms to the friction ridge structure of the finger depositing the print.
DFO Treatment
DFO (1,8-Diazafluoren-9-One) is a Ninhydrin analog that reacts to amino acids, but it also has fluorescent properties. Here are the steps to treating a document with DFO: (Author’s Note! It is preferable to run these treatments in the crime lab since it is more efficient and much, much safer when a chemical fume hood [exhaust fan] is available!).
1. Place the object to be treated in a fume hood. In the case of a document, suspend it using evidence clips. Cardboard objects and pieces of wood may be placed on the floor of the fume hood. Be certain to treat all surfaces of each object, since you probably will not know just where latent prints may be found.
2. Spray a heavy coating of the reagent of both sides of the document. Be certain to be wearing latex or nitrile gloves to keep your fingerprints off of the document and to prevent your fingertips from turning color.
3. The document or object should be allowed to air-dry.
DFO Development of a latent palmprint. Examined with Alternate Light Source (ALS) (455nm) and viewed through an orange barrier filter.
4. If tray development is preferred, allow the document to soak for about 5 seconds, just dip and then hang it up to dry.
5. If no other methods are used to accelerate development, it could take several hours or more for latents to develop.
6. Acceleration may be used if available. Expose the document to heat at about 200-degrees. Prints will then pop out in a matter of minutes. Visible DFO prints are often a light pink color, but they usually produce bright fluorescence when exposed to an alternate light source.
7. Once the prints are visible, they must be photographed (with a scale).
After treatment and drying, the document is placed in a heat chamber (at about 200-degrees). The document should remain in the chamber for 5-10 minutes.
After removal from the heat chamber, examine the document under subdued room light using an alternate light source that operates in the range of 455, 470, 505 and 520nm. These light frequencies are available from Sirchie’s BLUEMAXX and megaMAXX alternate light sources. DFO is said to produce 2.5 times the number of latent prints than Ninhydrin.
Ninhydrin Treatment
Ninhydrin is mixed with several different solvents like Xylene or Acetone. Less hazardous formulas are also available since these two are highly flammable. This mixture may be supplied in an aerosol can or a manual pump spray bottle. It is also mixed and used in an open developing tray in the crime lab.
Ninhydrin processing should follow this order:
1. Place the object to be treated in a fume hood. In the case of a document, suspend it using evidence clips. Cardboard objects and pieces of wood may be placed on the floor of the fume hood.
2. Spray a heavy coating of the reagent of both sides of the document object. In the case of objects—be certain to coat all surfaces since you may not know just where latent prints were placed. Be certain to be wearing latex or nitrile gloves to keep your fingerprints off of the document and to prevent your fingertips from turning a purple color.
Ninhydrin. Fully developed Ninhydrin latent print.
3. The document should be allowed to air-dry.
4. If tray development is preferred, allow the document to soak for 5 seconds, just dip and then hang it up to dry.
5. If no other methods are used to accelerate development, it could take 24 hours or more for latents to develop.
6. Acceleration may be used if available. Expose the document to moist heat at about 200-degrees. Prints will then pop out in a matter of minutes. Visible Ninhydrin prints are purple in color. An effective method of acceleration is to apply moist heat from a steam iron. Cover the document with a towel before applying the steam iron to prevent scorching of the document or object.
Even if prints are enhanced using the above methods, re-evaluate the results after waiting about 24 hours.
Ninhydrin prints may fade over a period of time so it may be advisable to use a Ninhydrin fixative (available from most Ninhydrin suppliers).
Alternative Methods
Should both of the above steps fail to produce useable latent prints, two alternative methods are available: Silver Nitrate and Physical Developer. Both of these reagents contain a silver salt, but they perform in a different manner. Silver Nitrate reacts to salt deposits in sweat while Physical Developer reacts to the presence of sebaceous secretions (oil).
shortwave ultra violet light source.
Silver Nitrate developed latent print.
Physical Developer, while still using a silver compound, is not as light sensitive as Silver Nitrate. It produces a gray latent print, which is also somewhat fluorescent, so a normal longwave UV light may be used. The best method for Physical Developer processing is tray development.
When processing certain kinds of paper it is a good practice to neutralize them first with a short bath in Maleic Acid. This is especially important for bleached (typically any white) paper as these will turn completely brown-gray without the neutralizing step.
Physical Developer latent print.
For more information about the tools that real-world CSIs use every day, you may download a complete catalog covering all of the techniques discussed in this article series. Visit this WEBSITE and download just the individual sections that interest you. The catalog is FREE. Check out pages 90-92 to see photographs of latent prints developed with the materials used in these articles.
You may also download a free technical manual that covers the various methods of latent print development. “Overview of Latent Print Development.”
Don Penven is a freelance writer based in Raleigh, NC. He has over 30 years of direct and indirect experience in law enforcement and crime scene investigation.
FBI Latent Print Hit of 2011
A Brief History of Fingerprints
The science of fingerprint identification, or dactylography, began nearly 4,000 years ago in the “Fertile Crescent,” the land between the Tigris and Euphrates Rivers in present day Iraq. King Hammurabi (1955-1913 BC) used finger seals on contracts and law officers of the day were authorized to secure fingerprints of arrested persons.
Little is known as to how the fingerprints were used. If actual point-to-point comparisons were made, people of that day surely had exceptional eyesight —since optical magnifiers weren’t invented until several millennia later.
In AD 650, nearly 600 years before Marco Polo visited “Cathay,” Chinese historian Kia Kung-Yen wrote of fingerprints used in an older method of preparing contracts. The law book of Yung-Hwui of the same period listed that the husband in a divorce decree had to sign the document with his fingerprint.
In AD 1100, Chinese novelist Shi-Naingan wrote in his book, The Story of the River Bank, “He compelled them to ink their fingers to record their fingerprints.”
In the late 1700’s, a German doctor, J.C.A. Mayer, reported that fingerprints are never duplicated by nature. A very astute observation — but Dr. Mayer left it at that.
Decades later, a student publishing his doctoral thesis in 1823 described fingerprint types and classified them into nine major groups. But author Johannes E. Purkinje gave them no identification value.
Most historians credit Sir William Herschal with being the first person to definitely use fingerprints for identification purposes. While working for the East India Company in Bengal, India, Herschal had natives place their palm prints on contracts and receipts. In 1858, when he began the practice, the idea was probably based on superstition; but Herschal quickly saw the value of fingerprints as a positive form of identification.
The first person given credit for using fingerprints to solve a crime is Henry Faulds. Faulds wrote in Nature magazine that when bloody finger marks or impressions on clay, glass, etc. exist, they may lead to the scientific identification of criminals. Faulds’ “chance impression” resolved a case of “…theft of rectified spirit.”
Up to this time, no unified system of physical identification existed beyond a general description of age, weight, marks, scars and so forth. Alphonse Bertillon, a French anthropologist, changed all that by introducing his system of “Anthropometry,” which consisted of exact measurements of various parts of the body (upper and lower arm, head, legs, etc.) A year later, in 1883, The Bertillon experiments were given permanent status and most countries in the Western world adopted the system.
In 1888, Sir Francis Galton, a noted British scientist, prepared a talk for the Royal Institute on Bertillon’s system, which kindled his interest in fingerprints. His research led to a meeting with Herschal and he built his knowledge from Herschal’s material. Galton went on to devise a classification system and he defined various points of identification in a fingerprint — known as “Galton Details,” or fingerprint minutiae.
Considerable progress was being made on this side of the Atlantic, too. Juan Vucetich set up Bertillon’s system for the LaPlatta, Argentina, police in 1891. This same year, he developed a classification system and began filing fingerprint records accordingly. The Vucetich System
is still in use in many Spanish-speaking countries.
Also in 1891 Sir Edward Richard Henry, Inspector General of Police in Bengal, India, experimented with Herschal’s fingerprint system. He then visited Galton and later developed his own classification system. A modified form of the Henry System is the basis for fingerprint classification and filing throughout much of the world today.
Henry eventually joined the Metropolitan Police (Scotland Yard) where he first set up the Bertillon system (in 1894), and later he initiated his fingerprint identification methods. In 1918 Henry was dismissed from the job following accusations of “oppression and injustice.”
More fingerprint work in South America led to the solution of a homicide using fingerprint evidence — the first such case in recorded history. Police Inspector Alvarez of LaPlatta, Argentina, solved the “Rojas Murder Case” with a bloody fingerprint found on a door. In 1896, anthropometry was abandoned in Argentina in favor of fingerprint identification.
The use of fingerprint identification in the United States was slow to develop. Most identification bureaus were locked into the Bertillon system until the now-famous Will West case at Leavenworth prison. When Will West arrived to serve his sentence in 1903, identification personnel insisted that he had been an inmate before. After being subjected to the Bertillon measurements, officials found the file of one William West, whose measurements were virtually identical to the person calling himself Will West. Even their photographs showed a remarkable resemblance.
But William West was still in prison serving a murder sentence. Their respective fingerprints were
taken, compared, and they bore no resemblance. This unique case established the value of fingerprint identification in this country.
It is interesting to note that later research indicates that Will and William West were most likely monozygote (identical) twins who were separated at a young age.
In 1904 the St. Louis, Missouri, Police Department was the first agency to set up a fingerprint bureau. Meanwhile, the International Association of Chiefs of Police (IACP) had established a central fingerprint file in Chicago. The complete file of some 810,000 records was turned over to the newly formed Identification Division of the F.B.I. Today the F.B.I. files contain several hundred
million record cards.
Advances in the state-of-the-art have led to computerization of fingerprint record files. Automated Fingerprint Identification Systems (A.F.I.S.) are in operation in many parts of the country. A.F.I.S. not only stores record cards in computer memory, it will match latent fingerprints from crime
scenes to its data bank. A well-known example of the speed of an A.F.I.S. at work was in California.
A latent fingerprint was entered into the system, and less than four minutes later the print was matched, and a killer who had eluded police for six years was identified and shortly apprehended.
Every human being carries with him from his cradle to his grave certain physical marks which do not change their character by which he can always be identified and that without shade of doubt or question these marks are his signature…and this autograph cannot be counterfeited, nor can he disguise it or hide it away. This ‘signature’ is each man’s very own — there is no duplicate of it
among the swarming populations of the globe. This autograph consists of the delicate lines or corrugations with which Nature marks the insides of the hands and the soles of the feet.
Pudd’nhead Wilson
Mark Twain, 1894
BASIC FINGERPRINT PATTERNS
PlainArches
Tented Arches
Loops
Plain Whorls
Double Loop Whorls
Central Pocket Loop Whorls
Accidental Whorls
