தடயவியல் ஆராய்ச்சி இதழ்

ANALYSIS OF UNUSUAL TRACE EVIDENCE- PAINT & GLITTER

Abstract

Simranjit Kaur,* Himanshu Chauhan, Simran, Saurav Kumar and Aishwarya Sunil

Trace evidence are types evidence evolved when an object comes in contact with a surface (based on Locard’s exchange principle). Locard’s exchange principle states that: Every contact leaves its trace”. Whenever two objects comes in contact there is transfer of substances between them. They are microscopic in nature because it is difficult to detect to our naked eye. These types of evidence are crucial for the investigation and also help in reconstruction of the crime scene. Unusual trace evidence is a unique set of evidence found in the crime scene that will be play an important role in investigation. Trace evidence refers to minimal amount of sample particularly fibres, glass, hair, fingerprints, saliva, paint chips, glitter etc. The trace evidence presence depends on persistence of the evidence. The extent of persistence of evidence depends on size and shape, amount deposited, environmental factors and time.

Paint is a pigmented liquid composed of pigment, binder, liquid and additives. Used for protecting, decoration and for providing texture. Paint chips are mainly encountered in cases of hit and run, burglary, kidnapping, sexual assault and homicide. Paint evidence comes under two main categories class and individual. Class characteristics can be examined through chemical analysis of each layer as the manufacturer uses different combinations.

The paint analysis is performed in three forms they are mechanical, physical, and chemical. The mechanical involves by making a physical matches, chemical involves by determining the chemical composition and finally physical which relates to the color, texture, pattern and appearance. The paint from a vehicle can be traced based on specific modal and make as the manufacturer will mix different constituents with a specific formula which helps in curbing the suspect. Here in this project, we have performed the paint examination based on the following: physical examination, microscopic examination, solubility test and instrumentations.

Glitter as a trace evidence is found in cases of sexual assault, robbery, kidnapping, and accidental cases. It is collected by using a cello tape or post it- notes. The characterization of glitter is performed by using various techniques such as stereomicroscopy, FT-IR and SEM/EDX. Glitter is analysed based on their color, shape, size, thickness and specific gravity etc.