Crime Laboratory
The mission of the Crime Laboratory is to provide our community with
quality forensic science and excellent service.
The Crime Laboratory is one of the three sections of the Forensic Division within the Investigative Services Bureau. The Tucson Police Department Crime Laboratory is the oldest crime laboratory in Arizona, founded in 1960. The laboratory’s initial home was in the Investigative Division located on the fourth floor of the Parkview Hotel (in the vicinity of Congress Street and Meyer). In 1962, the laboratory moved to the basement of old City Hall. In 1972, the laboratory moved into its third home, the first floor of TPD Headquarters, 270 South Stone Avenue. In April 1989, we moved to our current location on the second floor of the west wing of Headquarters.
This laboratory was one of the first municipal crime laboratories in the United States to gain national accreditation (1993) by the American Society of Crime Laboratory Directors-Laboratory Accreditation Board (ASCLD-LAB).
Our laboratory is a full-service forensic laboratory (except limited toxicology) organized into six operational units: Forensic Biology (DNA), Comparative Analysis, Latent Prints, Chemical Analysis, Computer Forensics and Administrative Support. We have a staff of 31: a Crime Lab Superintendent, a Quality Assurance Manager, 5 Crime Laboratory Coordinators, 20 Criminalists, 1 IBIS Technician, 1 Computer Forensics Detective, and 2 administrative professionals.
For additional information, contact Susan Shankles, Crime Lab Superintendent.
Forensic Biology Section
This section has two major functions. The first is to identify biological materials (“Is this red stuff really blood, or is it lipstick?”). This is done using a series of microscopic and/or chemical tests. Our second major function is to identify the donor(s) of any biological materials relevant to a crime scene (“Is it the victim’s blood on the suspect’s cuff, or is it his own blood from when he cut himself shaving?”). We do this by examining portions of the DNA (the cells’ molecular blueprint). A complete copy of an individual’s DNA is found in most cells in their body. Further, body surfaces are lined with epithelial cells, which are continuously being sloughed off and are sometimes transferred to objects with which they come into contact. These epithelial cells are a good source of DNA and can be found in saliva (such as lick/bite marks, drink containers or envelopes and stamps), nasal mucus, fingernails, etc. We are also linked to CODIS (Combined DNA Index System), the convicted offender national database. This section has six Criminalists and one Crime Lab Coordinator. For additional information, contact Robert Blackett, Forensic Biology Coordinator/DNA Technical Leader.
Comparative Analysis Section
The Comparative Analysis section of the laboratory consists of two disciplines, Firearms and Trace Evidence. Most of the analyses are subjective in nature, meaning that the examiner relies heavily upon observation (rather than instrumentation) to make a determination. The training period for a new examiner runs from six months for a Fire Debris Examiner to two years for a Firearms Examiner. This is strictly on-the-job training and is not available at universities. The minimum requirements, however, include a Bachelor of Science Degree in a physical science.
Comparative Analysis Section ─ Firearms Identification
Two fulltime Firearm Examiners, an IBIS technician and one Coordinator currently staff this unit. They examine expended cartridge cases and bullets from crime scenes to determine if they can be linked to a specific firearm. Examination of the bullets and/or cartridge cases also allows a determination of the type of weapon used, information that is often useful to the case detective. Comparisons are conducted using a specialized light microscope that allows the examiner to view both the evidence sample and the test sample simultaneously. Other examinations performed by Firearm Examiners include function and accuracy tests, trigger pull measurements (the force required to fire the weapon), muzzle-to -target distance determinations, and serial number restorations. The laboratory participates in a statewide computer database, NIBIN (National Integrated Ballistics Information Network Program), that links firearms from crimes in multiple jurisdictions. For additional information, please contact Frank Powell, Comparative Analysis Coordinator.
Comparative Analysis Section
Trace Evidence
One fulltime Analyst staffs the Trace Evidence Section. Trace evidence can include such things as hair, fibers, fire accelerants and explosives. The TPD Crime Lab currently examines fire debris evidence for the presence of ignitable liquids and examines explosives and explosive residues evidence for the presence of low explosives, pyrotechnic explosives, high explosives, or any combination of chemicals that can cause an explosion. These are done with high tech instruments and specialized microscopes. For additional information, please contact Frank Powell, Comparative Analysis Coordinator.
Latent Print Section
Previously part of the Identification Section, the Latent Print Unit (LPU) became a part of the Crime Laboratory July 1, 2001. Six Criminalist Latent Print Examiners and a Crime Lab Coordinator currently staff this unit. Members of the LPU are responsible for all examination of crime scene latent prints to known fingerprints, laboratory examination of evidence for latent prints, and tiretrack and shoeprint analyses. In addition, they are on call to assist investigators for major crime scene processing. Another responsibility for the unit is the searching of crime scene latent prints through Arizona Automated Fingerprint Identification Section (AZAFIS). AZAFIS cases are run when no suspect information is available, and we have made “cold” hits on over 25% of our cases.
Chemical Analysis Section - Drugs
We analyze the powders, tablets, capsules, and unknown substances that are suspected of being dangerous drugs or narcotics. These can be as simple as an aspirin tablet or as complex as a dozen samples from a suspected drug lab. We go to court and give testimony on all of our findings. This section includes three Criminalists and one Crime Lab Coordinator. Contact Lisa Windsor, Chemical Analysis Coordinator
Chemical Analysis Section - Toxicology
This section analyzes blood samples for alcohol content and maintains the Department’s Intoxilyzer instruments. We are responsible for training officers in the operation of the Intoxilyzer. We go to court and give testimony on all of our findings, from drug cases to suspected driving under the influence of alcohol cases. This section includes two Criminalists and one Crime Lab Coordinator. Contact Terry Gallegos, Chemical Analysis Coordinator.
Computer Forensics Section
In April of 2004, a new police detective position was added to the Crime Lab – that of Forensic Computer Analyst. Detective Rob Reed handles the analysis of hard drives and data for investigative purposes. Contact Detective Robert Reed.
