Biological evidence is a very broad category of evidences. It is a physical evidence classified based on the nature of the evidence. The word biological derived from the word biology, referring to living organism where else evidence is define as something legally submitted to a competent tribunal as a means of ascertaining the truth of any alleged matter of fact under investigation before it or information that is used in a court of law to prove something.
Therefore, biological evidence can be referred as biological materials or substances such as hair, tissue, bones, teeth, blood, semen or other bodily fluids including items containing biological material and used to corroborate and provide mean of proofing statement or claims in trials.
Types of Biological Evidence
As the term signifies, biological evidence comes from various sources of origin. It can be from human, plants or animals origin. Pollen, algae, fungi and diatom are examples of evidence from plants. Likewise microbes and insects are evidence from animals. For the benefit of the reader, this article will focus on biological evidence of human origin. Hence, the term biological evidence in the rest of the article is referring to human origin biological evidence.
Biological evidence includes:
- Blood and blood stains
- Semen and seminal stains
- Tissues and cells
- Bones and organs
- Fecal and fecal stains
- Stomach contents
- Ear wax
Sample like blood, urine, vomits and stomach contents are very useful in this analysis. The detection, identification and quantification of toxicology relevant substances and the interpretation of the results from this biological evidence aid in investigation on various cases such as death investigation, poisoning and drug use or abuse. Among the common analysis in toxicology are blood ethanol analysis, carbon monoxide analysis and pesticide (paraquat /organophosphate) analysis for poisoning.
- DNA Analysis
DNA analysis is generally limited to things that are biological in nature. Almost all the biological evidence are applicable for DNA analysis except to those bodily fluid without nucleated cells such as tears, perspiration and serum. DNA can also be trace in the sample of hairs with follicles where the DNA are extracted from the cell of follicles. Information gathered from the analysis will be used as for comparison or confirmation of unknown source collection during investigation.
- Histopathology Examination
Tissue can serve as an important sample especially for histopathology examination. Tissue sample usually taken during post-mortem or biopsy and have to go through a numerous processes before being able to be examine under the microscope. Through histopathology examination, we can see the changes to the body up to the cell level. Information detected can be very valuable for further investigation.
Under this analysis, bones and remains are the sample needed. The analysis on the bones can help:
- to differentiate between human and animal bones
- to determine the gender, approximate age and height of the victim
- to determine the cause of the death through the injuries on the bones
All biological evidence is subjected to deterioration. Therefore collection and storage is very crucial step in ensuring evidence is safely preserved and also contamination avoided. Adhering to proper evidence collection and preservation will help in retaining useful information that can be obtained later from any specific analysis.
In Malaysian scenario more than one personnel or agencies usually involved in different stages of investigation. The evidences will be transported from one personnel or agencies to another. Therefore, it is essential to ensure the safety and integrity of the evidence preserved all time such as having a suitable medium or mechanism of transportation for specific samples and with all the necessary documentation. This is to keep the chain of custody of the sample intact all time and legally accepted by court without any reasonable disputes.
- Abacus Diagnostic : Dramatically Improving Crime Scene Investigation (2014), Modern Methods of Collection and Preservation of Biological Evidence for Human Identification by DNA Analysis. Retrieved 01, 22, 2014 from tp://www.abacusdiagnostics.com/Modern_Methods_of_Collection.pdf
- Crime Scene Investigator Network (2000-2014), The Biological Evidence Preservation Handbook : Best Practices for Evidence Handler. Retrieved 01, 19, 2014 from http://www.crime-scene-investigator.net/BiologicalEvidencePreservationHandbook.pdf
|Last Reviewed||:||23 August 2019|
|Accreditor||:||Saravanakumar a/l Maniam|
|Reviewer||:||Dr. Khoo Lay See|