This photo shows a crime scene footwear print after having been developed and enhanced using black fingerprint powder.  The track had been deposited on polished floor tiles by a wet running shoe.  With oblique lighting, the latent print could easily be viewed but could not be advantageously recorded on camera.  Application of black fingerprint powder enhanced the track so that it was easily recorded on film.

     The contact areas of the damp runner actually removed wax from the tile surface as the culprit walked over the floor.  When the black fingerprint powder was applied, it stuck to the remaining waxed areas but not to the areas where the wax had been removed.  It created what is called a ‘take-away’ or a negative pattern.  This process tends to require considerable amounts of black powder and vigorous brushing techniques and even some heavy guttural breathing directly on the pattern.  As such it can be a very dirty method, but it yields excellent results as can be seen. 

     The Forensic Identification of footwear has come a long way in the past twenty-five years.  Over the years, many crime scene investigators have passed up what may have been incriminating evidence simply because they did not know how to properly process and compare it.  Mike Cassidy started the ball rolling in this country to show that footwear were an integral part of crime scene evidence.  Others have advanced the process so that now footwear ‘idents’ are usually more common than fingerprint identifications and can actually be more incriminating, depending of course on the circumstances.  A school janitor usually takes great pride in his floors even though fingerprints remain everywhere in the building.

     However, footwear comparisons require considerable training and preparation.  One can easily be ‘fooled’ by class characteristics.  It is certainly an area that requires great care in utilizing the ACE-V process correctly.

In addition, to ensure the value of the evidence for court purposes, certain protocols must be followed at the scene both for the location, protection, and recording of the evidence.  Any investigator attending a crime scene without a good quality flashlight is not really a crime scene investigator at all.  Even before entry to the scene, he must be observant for footwear and tire tracks outside the building.  With any crime scene, there is one thing that is definite.  The culprit has touched the floor and/or some other surface with his footwear.  Any hard surface such as tile, wood, stone, etc will either receive a deposit from or give up surface material to the footwear.  Even carpets can provide footwear evidence.  I have frequently provided images of runners to investigators that show definite size and shape characteristics.  This alone is sufficient to eliminate possible suspects, something that is most helpful to the investigator when such lists are long.  Usually oblique light from a strong directed light source will make the details of the latent footwear print visible.  The trick then is to enhance it so that it is recordable by the camera.  Today there are numerous methods and each requires training and experience so that it can be used to its advantage. 

          Without any doubt, the camera that over the years has provided the best practical quality & versatility for crime scene imaging is the 35 mm SLR film camera with a normal 55 or 60 mm lens.  I have used all formats from 4 x 5 inch crown graphics, 120 mm medium format, 35 mm format and various digitals.  With the equivalent of nearly 90 MB of data in a single frame, few digital cameras in use even today are capable of even approaching the quality.  While most Forensic Identification Sections have moved away from film cameras and darkrooms, there definitely is a void in the image quality previously available with film when crime scene photos are not recorded by that method.  But with today’s emphasis on instant photos quickly disseminated to numerous parties, the digital image can be distributed via email or printed from a portable printer for a cheap and quick hard copy image.  But with the proliferation of software capable of adjusting and/or altering the digital image, one must be careful to use the correct protocol to ensure the admissibility of these photos in court.  

     Several years ago, a camera store owner told me that if he were ever a jury member, he would never accept as evidence a digital photograph because of what can be done to alter the image.  My comment was that with my film background, I certainly would be able to add his image to any photograph that I desired, and that I could produce a negative for him to 'prove' its authenticity, if that was all it took.  However, the credibility of the court witness is of paramount importance in the admissibility of crime scene photos. 

     As a word of caution, one must expect to find footwear on any surface and sometimes in large quantities.  I know of a homicide case that was lost because one very senior forensic identification crime scene investigator felt that it was unnecessary to properly record each and every footwear track in the actual crime scene.  While one must use one’s judgement at normal crime scenes, certainly a homicide or other violent crime scene demands the ultimate effort, knowing full well that every bit of evidence will be thoroughly scrutinized, especially that which could have been overlooked and missed.  Remember that if one is following the principals of ACE-V, one cannot evaluate a piece of scene evidence before it is recorded for later analysis, especially when there is nothing with which to compare it.  And if it is not recorded accurately, there can be no verification of the evaluation, which therefore cancels out the whole effort of processing the crime scene. 

     It has been proven time and again in this country that Police investigators are not infallible.  Therefore the verification of physical evidence by peers is an absolute requirement in our justice system.  There is an onus on the crime scene investigator to do a full and complete scene investigation and evidence collection.  Anything less could lead to the erroneous conviction of an innocent suspect.