Types & Lifting methods of Footprints

What is Footprint?

Footprints are the impressions or images left behind by a person, during walking or running, usually when the dust particles, soil(mud), grease, oil, blood, or any other material stick to the sole of the footwear.

It is also produced on the mud, snow, etc.

Location of Footprints-

AT THE SCENE OF THE CRIME

• The impressions of the foot may be caused by mud, sand, snow, grease, etc.
• If the footprint is produced on smooth and hard surfaces like floor, road, etc. giving a 2D print.
• If the footprint is produced on a soft surface like snow or mud etc. giving a 3D print.

AROUND THE PLACE OF OCCURRENCE OF CRIME

• Footprints may be found in the fields, courtyard, floor of the room, walls, staircase, table and chair, drain pipe, etc.
• If the culprit gets his foot or footwear smeared in blood, he is likely to leave prints in blood.

The scope of a complete examination consists of two main functions:-

• 1st the recovery process, which includes the discovery and preservation of the prints and,
• 2nd the identification process involves evaluations, comparisons, and findings related to recovered impressions.
• In almost every criminal investigation it is necessary to determine and prove that a particular person or persons may or may not have been present at the scene of the crime.
• For this reason, the collection, preservation, and analysis of physical evidence have become more frequent in the law enforcement community.

How to preserve the footprints?

• Footprints on the walls should be covered with paper.
• If the footprints are inside the room and they can not be immediately removed or reported then the room should be locked.
• If the footprints are in open places, where persons ignorant of the occurrence generally come and go, it may be necessary to post a guard, besides covering the prints.
• If the footprints are on easily removable articles, these should be taken into custody.

Types of footprints-

3 Categories;

1. Visible prints: It is also known as patent prints. It is two-dimensional.

2. Plastic prints: These impressions occur when the footwear step into a soft surface, such as deep mud, snow, wet sand, etc. It is three-dimensional.

3. Latent prints: It is hidden from the eyes.

Lifting or Recording of FootPrints-

1. Photography

A 2D evidence where the impression is photographed and captured for the record.

Prints that can not be lifted easily are photographed with polaroid 665 black and white film loaded in a polaroid CU-5 camera.

2. Casting

A 3D evidence in which the impression of the foot is reproduced. For instance, one method of casting is done by plaster of Paris. A ruler is first used to measure the size of the impression. Then clean the impression carefully without disturbing it. Then Plaster of Paris is poured in the impression and add some straw or dried grass(to make the cast stable bcoz only plaster of Paris is much brittle) then again add plaster of Paris and allow it to set. Once the plaster dries up, then remove the cast from print and the cast created to be examined further.

Note:- To produce the cast on the snow surface the method is the same but before starting this firstly spray the sulfur solution on the footprint to prevent the snow from melting.

3. Lifting

This method is used when a foot impression is a visible print on an item. An adhesive paper is used to transfer the print.

4.      Tracing

It is used for 2D footprints. For tracing footprints, a glass sheet is placed over the dried 2D print carefully after taking the images of footprint by using a scale for exact measurements, then make the outline by tracing the footprints over the glass sheet by using a permanent marker.

There are certain methods for the footprints which can not be lifted are collected by the following;

a) Adhesive filter

b) Gelatin filter

c) Electrostatic dust print lifting device.