Biological evidence consists of bodily fluids and tissues. Biological evidence has particular significance since DNA analysis can be conducted in many instances. This DNA analysis may identify the donor. Examples of biological evidence containing DNA include:
- Sloughed skin cells.
- Fecal material.
A DNA profile may also be obtained by swabbing items thought to have been handled by a perpetrator. This type of evidence is sometimes referred to as "touch DNA."
The power of DNA testing is such that examination of biological items can produce very compelling evidence. However, attention must be paid to safety, contamination and degradation issues.
Often biological evidence, including touch DNA, is not visible to the naked eye. To aid in locating possible biological fluids, the following enhancement techniques may be useful:
- Visual inspection.
- Alternate light source.
- Chemical enhancement, such as luminol
Additional Online Courses
- What Every First Responding Officer Should Know About DNA Evidence
- Collecting DNA Evidence at Property Crime Scenes
- DNA – A Prosecutor’s Practice Notebook
- Crime Scene and DNA Basics
- Laboratory Safety Programs
- DNA Amplification
- Population Genetics and Statistics
- Non-STR DNA Markers: SNPs, Y-STRs, LCN and mtDNA
- Firearms Examiner Training
- Forensic DNA Education for Law Enforcement Decisionmakers
- What Every Investigator and Evidence Technician Should Know About DNA Evidence
- Principles of Forensic DNA for Officers of the Court
- Law 101: Legal Guide for the Forensic Expert
- Laboratory Orientation and Testing of Body Fluids and Tissues
- DNA Extraction and Quantitation
- STR Data Analysis and Interpretation
- Communication Skills, Report Writing, and Courtroom Testimony
- Español for Law Enforcement
- Amplified DNA Product Separation for Forensic Analysts