Shoe Print
When a person walking or running he left the impression or images behind him/her .
These impression are the footprints. Animals left hoof prints and paw prints
with hooves or paws rather than feet , while "shoe prints"
is the term used for prints made by shoes.
Shoes create impressions/images at crime scene and they are extremely
informative to the forensic investigator.
When a person walks the sole of shoe picks up various materials ,
and these materials when transferred to other surfaces , create a impression
that can reveal the pattern of the sole. Investigators lookout these prints at
the entry and exit of a crime scene and on carpet , linoleum , paper , dust
and on soil around the crime scene. shoe print in a pool of blood serve as
incriminating evidence . Footwear evidence help the investigators with
certain information which leads the way to suspect. Footwear evidence , provide
the make , type , description , approximate size , the path through and away
form the crime scene, the involvement of number of suspects .
It also emphasis on the wear patterns (patterns that form on a shoe ,
depending on how the wearer walks) or any specific damage (nicks and cuts, etc.) to the shoes.
There are three types of shoe prints -
Patent or visible ,
plastic , and latent.
A patent or visible print is a transfer of material (like paint or dirt) from the shoe or tire to the surface. This type can be seen through naked eye without additional aids (no powder or chemical examination needed) . For example, bloody shoe print on flooring or tracks left by muddy tires on a driveway and a dirty footprint on the floor .Similar techniques like fingerprinting are used to lift these 2D impressions . Dust impression found on a masonite surface are illuminated with oblique lighting.
When a shoe sinks into a soft substance like snow or mud a plastic shoe print occurs. It is a three-dimensional impression left on a soft surface such as shoe or tire tracks left in sand, mud or snow. These 3D impressions are preserved by photographs or by casting. Without cleaning or brushing anything the cast , it is put into a cardboard box or paper bag and transport to the lab , where it is examined for trace evidence such as tar , soil or other materials that might reveal where the suspect has been.
Latent shoe prints are not visible to the naked eye and occured
on a hard surface like glass or concrete. these prints created through static
charges between the sole or tread and the surface. These prints then visible by
dusted with special powders , chemicals or alternate light sources or by electrostatic
lifting , and by making plaster casts . Photograph is always taken .Shoe prints
on a tile or hardwood floor , window sill , or metal counter are some examples.
Footwear Impressions are not properly executed -
Reason behind this is the lack of education and training for
proper search , collection and preservation of the evidence .The evidence is
undervalued and not successful due to incomplete search of the crime scene. Due
to some weather conditions it is easily eradicated and there is the possibility
that the impression has been intentionally destroyed. They are eradicated by
people and vehicles approaching the crime scene from the same direction of
entry or escape that the suspect might have taken. Isolation of the area is
essential.
There are many ways to secure footwear evidence at the crime scene. After securing the area and establishing the crime scene the officer should make sure the entire crime scene is marked off using crime scene barricade tape, and no one should be allowed to enter until the crime scene investigator reached. Protection from weather done by placing boxes , cones, etc. over the impressions. Don’t disturbed the evidence before taking photographs.
How sample is collected -
Casting is used in collection method for impressions in
soil, snow or other soft surfaces . Casting uses a powdered stone material ,
such as dental stone/plaster of paris , that can be mixed with water and poured
into the impression. When it dries, it is resulted in a 3D model of the impression. For imprints the entire object containing the imprint
, such as cardboard or whole sheet of paper with a shoe print is collected. If
the print is on a bank counter , lifting technique is used to transfer the
imprint to a medium that can be sent to the laboratory.
Various lifting techniques for shoe print are –
Adhesive lifter - Usually used with fingerprint powders .
Adhesive lifters , lifts the imprint from smooth , non-delicate surfaces like
tile or hardwood floors , metal counters etc.
Gelatin lifter – It lifts the prints from any surface ,
including porous , curved , rough and
textured surfaces. It is a sheet of rubber with a low-adhesive gelatin layer on
one side .It is more flexible than any adhesive lifter .
Electrostatic dust-print lifting device - It
electrostatically charge the particles within dust or light soil , which then
attracted and bonded to a lifting film. This tool is best for collecting dry or
dusty residue imprint on any surface , even the skin of a cadaver.
Photographs of the impression evidence with its location in
related to the rest of the crime scene were taken. Alternate light sources or
chemical enhancers are used to capture as much detail as possible, especially
in case of latent imprints. Photographs taken at a 90° angle to the impression
are best.
The evaluation and comparison of impression evidence performed
by well-trained footwear examiner. These expert received extensive training on
footwear impression , its detection , development , handling and examination
procedure . The IAI also certifies footwear (but not tire track) examiners.
For examination and comparison shoe print examiners use tools
such as dividers , special calipers , lighting and low magnification. They examine
the length and width of the impressions, and then compare it with the crime
scene print or impressions.
Side-by-side comparison is done
by placing the known shoe print alongside the print found at crime scene to
examined the corresponding areas. Test prints were also compared . During the
comparison Digital images on computer monitors can also be used .It is possible
from the size of a sole to determine
Manual identification is laborious so automated methods used by shoe print examiners. In automatic shoe print identification Shoe print Extraction is very important , as we encountered the problem of isolating the shoe print foreground (impressions of the shoe) from the remaining elements (background and noise).
MR. DEEPAK PAWAR has been working as Finger Print Expert / Police Officer in Finger Print Bureau , Delhi Police at New Delhi since 2001 . He is the senior most Finger Print Expert , attending / visited several scene of crime and solved many crime cases .He has passed M.Sc (Chemistry) and he is the Member of International Association of Identification . He is the Member of Delhi Police welfare association . He is supervising the Forensic , New Delhi District , Mobile Crime Team . He is one of the Expert in the Special Investigation Team held for investigation of important cases . He has been giving fingerprint proficient training to Delhi Police personnel's . He has been Presented / giving lectures on topics related to forensic science . He is also making examination paper of Finger Print proficient course . He is awarded with Police Medal by MHA and Delhi Police.