OC Crime Lab provides all law enforcement agencies with forensic evidence examination and crime scene response services to recognize, collect, and evaluate physical evidence from criminal investigations. The Division has grown from a one-man operation in 1948 to its present day staff of 154 technical and support personnel. The Division is equipped with state-of-the-art technology and instrumentation and is internationally accredited by the American Society of Crime Laboratory Directors / Laboratory Accreditation Board. OC Crime Lab is composed of four Bureaus: the Criminalistics Bureau, the Toxicology Bureau, the Identification Bureau, and the Cal-ID Bureau (Automated Fingerprint Identification System).
The Criminalistics Bureau is made up of several sections, which are defined by the type of physical evidence they process. The Firearms section examines firearms and tool marks, linking bullets and cartridge casings to the weapons that fired them, as well as linking tool marks left at a crime scene to the tool that made them. The Firearms section also uses a sophisticated computer imaging database, called NIBIN, to link firearms evidence from different jurisdictions throughout Southern California. The Trace Evidence section examines microscopic evidence such as hairs, fibers, soil and paint that are left at crime scenes or found on individuals, as well as looking for traces of ignitable liquids and explosives. Other Trace section examinations include gunshot residue testing, lamp filament on-off determination and the analysis of unknown materials. The DNA section examines biological evidence left behind at crime scenes and develops DNA profiles for comparison to known suspects or comparison to known offenders in local, state and national DNA databases. The DNA section has also been active in examining old unsolved cases and is pioneering work recovering DNA in the area of touched or handled objects with no visible biological material. The Controlled Substance section tests substances seized during drug investigations to determine if they contain illegal drugs and also responds to requests to investigate clandestine drug manufacturing labs. The Questioned Document section analyzes documents to determine document authenticity and the identity of the author via handwriting comparisons. Finally, the Evidence Control Unit provides evidence custodian services to the technical staff of the laboratory.
The Toxicology Bureau provides analysis for drugs and poisons from coroner’s cases in blood and tissue samples to assist in death investigations, performs blood and breath alcohol analysis to determine the amount of alcohol ingested by a person suspected of driving under the influence, and analyzes blood for the presence of drugs ingested by those arrested for being under the influence of drugs.
The Identification Bureau performs crime scene investigation services including general photography, aerial photography, crime scene documentation and scene diagramming, scene and evidence processing for latent fingerprints and other physical evidence, and latent fingerprint comparisons. The Identification section also compares shoeprints and tire tracks left at a crime scenes and operates a photo processing lab and professional photographic studio. The Clerical section performs crime scene dispatch services and supports the overall Division operations with data entry and the maintenance of case records.
The Cal-ID Bureau provides rapid identification of arrestees in the county for prior arrest records, to provide identification of crime scene latent fingerprints and to identify new arrestees to any unsolved crimes in the county where crime scene latent fingerprints were found. The Bureau recently replaced the County’s livescan devices which electronically capture subject fingerprints with state-of-the-art high resolution imaging.