2530 Arnold Drive, 2nd Floor
Martinez, CA 94553
Phone: (925) 335-1600
Fax: (925) 335-1601
Forensic Biology (DNA)
Biological screening/DNA analysis includes screening evidence for DNA, generating a DNA profile, and comparing the profile to the submitted reference standards. This examination applies to all biological evidence including Sexual Assault Evidence Kits, clothing or bedding, swabs from a crime scene, trace DNA swabs, and reference standards (buccal swabs). The Unit uses mixture deconvolution software (STRmix™) which uses complex mathematical modeling in cases that may have previously been deemed uninterpretable. In cases in which a suspect has not yet been identified, or a potential suspect has been eliminated by comparative DNA analysis, the unknown DNA profile can be entered into a database known as CODIS.
The Combined DNA Index System (CODIS) blends forensic science and computer technology into a tool for linking violent crimes. The Forensic Biology (DNA) Unit uses CODIS to exchange and compare DNA profiles electronically, between local, state and federal agencies, linking crimes to each other and to criminal offenders. Analysts use CODIS to search DNA profiles obtained from evidence against DNA profiles from crime scenes, convicted offenders, and arrestees. CODIS is administrated by the Federal Bureau of Investigation and enables police from multiple jurisdictions to share leads and coordinate their investigations.
The Unit offers male specific DNA testing (Y-STR typing). This technology is especially useful for sexual assault evidence with a high ratio of female to male DNA.
The Unit offers free consultations for agency’s cold cases. The Unit can help strategize the best course of DNA Analysis for your evidence. We can tell you what evidence has been consumed, should be re-analyzed, as well as, whether any evidence may be amenable for a CODIS familial search and/or a genealogical search.
Comparative Evidence
(Firearm and Tool Comparisons)
Ballistic Imaging (NIBIN) analysis can link shooting scenes with a database search of cartridge cases. The Comparative Evidence Unit uses the National Integrated Ballistic Information Network (NIBIN) administered by the Bureau of Alcohol, Tobacco, Firearms, and Explosives to acquire digital images of the markings on cartridge cases recovered from a crime scene or test fires obtained from firearms. The NIBIN Program provides actionable investigative leads in a timely manner. NIBIN is the only interstate automated ballistic imaging network in operation in the United States.
Other Comparative Evidence services include Firearms Comparison analysis to determine if a cartridge case or bullet was fired or cycled through a firearm; Make & Model Determination analysis to generate a list of firearms that may have fired the cartridge cases and bullets from your shooting scene; Function Testing to determine a firearm’s operability, including its ability to fire, if it has been altered, if it is too short, if it is fully-automatic, and if it is an assault weapon; Serial Number Restoration to recover obliterated serial numbers; Sound Suppressor Determination to determine if it is a silencer as defied by the California Penal Code; and Unloading a firearm that is difficult to render safe.
Latent Prints
Latent prints are impressions or marks produced by the raised skin, known as friction ridges, on human fingers, palms, and soles of the feet. The Unit can Process Items for Latent Prints including analyzing your evidence for latent prints and comparing those prints to the listed individuals or searching for the prints in the ABIS database.
Automated Biometric Identification System (ABIS) is a sophisticated computer-based system which electronically encodes, searches, and stores the images of fingerprints and palm prints. “Known prints” or exemplars comprise a complete set of fingerprints and palm prints taken from a known individual. Typically known prints are obtained using a Livescan device. The analysts in the Latent Print Unit use ABIS as a tool to search unknown latent prints against the known prints in the database. The ABIS software looks for details in the print to find the best match in its database. Any potential matches or “hits” are evaluated by an analyst. Prints that do not “hit” will continue to search in the database.
Crime Scene Response
Crime scene responders are responsible for complex crime scene investigations using various types of equipment; developing, securing, and packaging physical evidence for scientific evaluation and comparison; preparing detailed reports on the observations and activities at the scene and testifying in court regarding the findings and processing methods used at the scene. Crime scene responders are responsible for the documentation, collection, processing, and examination of physical evidence from all Law-Enforcement Involved Fatal Incidents per the County protocol. Crime scenes may be documented by the RTC360, a 3D laser scanner with the ability to quickly scan the scene with full HDR images. The resulting output file allows law enforcement and the district attorney’s office to visualize the scene as never before.
