Specialties
Controlled substances and toxicology
- Crime lab analysts specializing in controlled substances and toxicology commonly examine body fluids (blood in particular) and tissues for the presence of drugs, alcohol, and poisons.
- Crime lab analysts frequently compare hair and body fluids for typing factors, including DNA analysis. DNA analysis is used to determine how frequently a person’s particular genetic code is found in a given population; forensic scientists as well as crime laboratory analysits isolate strands of DNA from an individual’s body fluids and compare that individuals’s unique DNA to the DNA of a sample of others. Due to its accuracy, DNA analysis has become very popular in recent years.
Analysis of a hair can determine a number of factors including whether or not the hair belongs to an animal or a human, diseases the person or animal has, the body area the hair came from, and, in some instances, a person's race. Via simple side-by-side comparisons, examination of hair at a crime scene can be matched to the person who left it there.
- Crime lab analysts are required to analyze the chemical composition of trace physical evidence including blood spatters, soil, paint, and glass. For example, blood spatters help reconstruct a crime scene: The patterns of spatters, the shapes of blood droplets, as well as the forensic analysis of the blood type and age indicate how and when a crime was committed.
- Document examination includes many areas of expertise, including document dating, forgery, handwriting analysis, computer printing, typewriting, and photocopying.
- Firearms examination involves matching identifying characteristics between a firearm and projectile and between a projectile and target. Typically, this includes matching bullets to the gun that fired them. Toolmark identification involves matching some identifying characteristics of a tool, such as a pry bar, to the object on which it was used, such as a door frame. It also includes explosives and imprint evidence.
- Fingerprinting, one of the oldest of the forensic analysis processes, provides a very reliable way of identifying an individual because everyones fingerprints are unique. And because fingerprints are formed underneath a person's skin, fingerprints are always the same — even after buring or scaring. Crime lab analysts match fingerprints recovered from a crime scene against the fingerprints of individuals on file to make a positive identification. Advanced digital technology now allows analysts to compare prints at an increadible rate of 400,000 per second.
- The psychophysical detection of deception exam (common know as the polygraph or lie dector test) is based on the scientific theory that when someone is lying, their body responds in an certain way despite any attempts to avoid detection. Crime lab analysts employ specialized electrical equipment to measure changes and fluctuations in internal body functions — including blood pressure, breathing, and pulse rate — in response to their questions and then they analyze the results.