CasTips02 –Recording Dust Print Impressions

Crime Scene Investigation-- The Recording Dust Print Impressions

By: Don Penven 

Dust prints occur at crime scenes as a result of two influences:

1. They are tracked into a structure as a result of dust, dirt, pollen or other foreign material adhering to the soles of shoes
2. Once inside the subject may walk through a dust covered area and will leave negative impressions—where the existing dust was removed by the footwear and will leave positive impressions in areas where the transported dust is deposited on floors.

The search for dust impressions must begin prior to any other activity except for rendering aid to injured persons.

The Search for and Recording of Latent Dust Prints

The first challenge is to locate any possible dust print impressions.  The most effective method available is a flashlight. If possible, darken the room (total darkness usually is not necessary).

1. Direct the light beam across the floor at floor level. Dust impression, if present, will become immediately visible. 
2. Mark each visible impression with an evidence marker such as an evidence tent.
3. Once all available impressions are located and marked, photograph them as follows:
   1. Using a tripod, position the camera directly above each impression—at right angles to the surface.
   2. Always include a scale in each photo taken
   3. Assuming you are using a digital camera (and if not, why not) use the flashlight beam as a light source or use a flash that may be extended from the camera via a flash extension cable. The light (or flash) should be aimed at an oblique angle similar to what you used to originally locate the prints. The digital camera will provide an immediate preview of the impression.
   4. Maintain a written log of each photo taken.
   5. Be certain to pin-point the location of the impressions on the crime scene sketch. 

Special Note: If the crime scene is being recorded on video, be certain to get video footage of the location of the prints as well as close-up shots. While video isn’t very useful in the actual comparison of the dust prints with a suspect’s shoes, it will give the jury a glimpse of what you were working with. 

Once you are satisfied with the quality of your photos you may consider recovering the impressions if you are equipped to do so. The next article in this series, PrinTips03 – Recovering Dust Impressions, will cover several methods for dust print recovery. 

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