Introduction

Biological evidence in forensic investigations holds paramount importance in identifying perpetrators and unravelling the truth behind criminal activities. This type of evidence encompasses various biological materials and substances that can shed light on the events surrounding a crime and aid in establishing the guilt or innocence of suspects.

As the term signifies, biological evidence comes from various sources of origin. It can be of human, plant or animal 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.

Derived from living organisms, biological evidence includes a wide range of sources such as blood, saliva, hair, semen, skin, nail clippings, and bodily fluids. Each of these elements can provide unique insights into a crime and the individuals involved.

One of the most valuable uses of biological evidence lies in DNA analysis. Almost all biological materials are applicable for DNA examination, except for certain bodily fluids without nucleated cells. Through DNA analysis, investigators can establish connections between suspects and crime scenes, corroborating eyewitness accounts and strengthening the case against the accused.

Histopathology examination, another critical aspect of analyzing biological evidence, is particularly relevant when dealing with tissue samples. These samples, obtained during post-mortems or biopsies, undergo meticulous examination at the cellular level. The information gleaned from histopathology can be invaluable in understanding the extent of injuries or illnesses related to the crime.

Biological evidence also plays a pivotal role in toxicology analysis. Blood, urine, vomit, and stomach contents can provide valuable information regarding toxic substances, drug use, or poisoning. This analysis is instrumental in death investigations and cases involving harmful substances.

Preservation and proper handling of biological evidence are of utmost importance to ensure its integrity and usefulness in investigations. With deterioration being a constant concern, meticulous collection, storage, and transportation protocols are essential to maintain the evidentiary value of biological materials.

Types of Biological Evidence

When an individual is accused of a crime, law enforcement and the prosecution use various types of evidence to identify the perpetrator and present a convincing case in court. The evidence introduced during the trial can consist of different forms, including documentary, tangible, and biological evidence. Among these, biological evidence plays a significant role in criminal investigations. Examples of biological evidence include:

1. Blood: Blood samples found at a crime scene or on objects can provide crucial information about the events that transpired. Blood analysis can reveal the presence of DNA, blood type, and other identifying markers.
2. Saliva: Saliva left behind on objects or at the scene of a crime may contain DNA, which can help link the suspect to the crime.
3. Hair: Hair evidence can be examined for DNA, which can provide valuable information about the individual linked to the crime.
4. Skin: Skin cells left behind, such as through touch, can potentially yield DNA evidence for identification purposes.
5. Semen: Semen is important biological evidence in cases involving sexual assaults or crimes with a sexual element.
6. Nail Clippings: Nail clippings can be examined for possible traces of biological material that may be relevant to the investigation.

The introduction of biological evidence at trial is essential to establish a link between the accused and the crime scene, potentially aiding in proving the defendant’s guilt beyond a reasonable doubt. Through scientific analysis of biological evidence, law enforcement and the prosecution can strengthen their case and bring justice to the victims of crime.

Other biological evidence includes:

• Urine
• Tissues and cells
• Bones and organs
• Teeth
• Faecal and faecal stains
• Vomit
• Stomach contents
• Sweat
• Ear wax

Analysis

Various analyses are conducted on biological evidence to aid in forensic investigations:

1. Toxicology: Samples such as blood, urine, vomit, and stomach contents are essential in toxicology analysis. Detection, identification, and quantification of toxic substances help investigate cases involving death, poisoning, or drug use and abuse. Common toxicology analyses include blood ethanol analysis, carbon monoxide analysis, and pesticide (paraquat/organophosphate) analysis for poisoning cases.

2. DNA Analysis: DNA analysis is applicable to almost all biological evidence except bodily fluids without nucleated cells, such as tears, perspiration, and serum. DNA can be extracted from hair samples with follicles. DNA analysis helps compare and confirm the source of unknown samples collected during an investigation.

3. Histopathology Examination: Tissue samples, often obtained during post-mortem or biopsy, undergo histopathology examination. This examination allows investigators to observe changes in the body at the cellular level, providing valuable information for further investigation.

4. Anthropology: Bones and remains are analyzed in anthropology to differentiate between human and animal bones, determine the victim’s gender, approximate age, and height, and ascertain the cause of death through injuries on the bones.

Important Notes

In the Malaysian context, cooperation among different agencies and personnel involved in various stages of investigation is crucial. Ensuring the safety and integrity of the evidence at all times, with suitable transportation mechanisms and comprehensive documentation, maintains the chain of custody and strengthens the admissibility of evidence in court.

In conclusion, biological evidence is a potent investigative tool that can unravel complex criminal cases and bring justice to victims. Advances in forensic science have expanded its capabilities, making it an indispensable aspect of modern forensic investigations. Proper utilization and understanding of biological evidence can lead to accurate and just outcomes in the pursuit of truth and the rule of law.

References

1. 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
2. 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