Crime laboratories play a vital role in the criminal justice process. Scientific testimony is often the deciding factor in the judicial resolution of civil and criminal cases. The results of scientific analysis of evidence in the blood, semen, shreds of clothing, hair, fibers, glass, paint, soil, bullets or bullet casings, impressions, and other physical indications left at the scene of a crime can seem more compelling to a jury than the testimony of eyewitnesses. The timely scientific analysis of any physical evidence relating to crimes against the citizens of the state is an integral part of the laboratory services. To support demands, forensic laboratory services are grouped into specialties, which include the analysis of different types of evidence. Body fluids like blood, saliva, semen, vaginal samples, and stains are examined and analyzed. Their identification and characterization can implicate or eliminate a suspect. The information derived from the examinations assists investigators as they reconstruct the events that occur during crimes, especially crimes against persons.

DNA testing of whole blood and dried serological stains has been added to the traditional serological analytical protocols or rules in this functional area. Experts examine firearms for operating features and defects. Bullets and shell casings may reveal unique characteristics, leaving telltale marks that help identify the firearms from which they were fired. Gunshot residue and patterns are examined to determine the proximity of a firearm muzzle to a victim. Tools often leave unique, identifiable marks on surfaces that may link suspects to crimes. Experts can restore serial numbers that have been altered on articles such as firearms, machinery, and office equipment. Using microscopic techniques and microanalytical instrumentation, forensic scientists can identify and compare small particles and fibrous materials; for example, fibers, hair, soils, paint, glass, wood chips, building materials, and vehicle head- and taillights. General Criminalistics physical evidence is examined to determine such things as patterns, damage, sequence of deposits, and sequence of events.

The physical evidence may include shoe prints, tire tracks, blood spatters, clothing, weapons, and wounds. Evidence associated with homicide, rape, robbery, and burglary, and other crimes, along with fire accelerants and explosives related to arson and bombing, are scrutinized by analyzing their chemical composition. The results of each analysis afford information that may connect the evidence to a suspect, victim, crime scene, and/or the crime itself. Controlled Substances Suspected evidence undergoes chemical analysis to determine its drug contents. Any evidence used in a crime involving possession, use, or sale of a controlled substance must be identified as a prohibited drug to establish that a crime was committed. Documents are examined to identify the writer and to detect a forgery or alteration in cases that involve checks, credit card receipts, robbery notes, fraudulent papers, prescriptions, extortion and ransom notes, obscene letters, illicit business records, lottery, and pull tab tickets.

Examiners process evidence and crime scenes for fingerprints and obtain post-mortem fingerprints. They locate, photograph, process, and compare latent prints to known candidates and prints in the Automated Fingerprint Identification System. Selected forensic scientists and latent fingerprint examiners from the crime laboratory are included in the Patrol Crime Scene Response Team. The team, made up of crime laboratory personnel and detectives from the Traffic Investigation Division, is available twenty four hours a day to assist local law enforcement agencies as they process the scene of a crime. Also, the team can help other agencies recognize, handle, preserve, and package physical evidence. Laboratory personnel also help reconstruct the events that occurred at the scene.