The DFS’ Forensic Science Laboratory Division (FSL) collects, examines, analyzes, and reports on physical evidence submitted in criminal cases. The FSL is authorized to examine evidence submitted by any DC governmental agency investigating a criminal offense. Federal agencies, such as the U.S. Park Police, are also able to use the services of the FSL.
Currently the FSL offers Forensic Biology, Materials Analysis, Firearms, and Fingerprint examinations.
- Forensic Biology: The analysis of biological tissues, such as blood, semen, skin, and hairs, for morphological and genetic characteristics. When compared to reference samples from a known source, modern forensic DNA analysis can be extremely specific about establishing identity.
- Materials Analysis: The analysis of physical materials both natural and manufactured, such as fibers, paint, and glass. These materials are highly complex and require a suite of methods to determine morphology, composition, and structure. Light microscopy, electron microscopy, infrared spectroscopy, microspectrophotometry (analysis of light in the ultraviolet and visible ranges), and other methods of spectrometry and chromatography are used to determine the classification and possible sources of materials ranging from nylon fibers to automotive paint to window glass, among many others.
- Firearms and Toolmarks Examination: The examination and comparison of firearms of all types as well as toolmarks left when a harder object comes in contact with a softer one. Firearms are used in many types of crimes, from homicides to robberies and assaults. The Unit evaluates the functionality of firearms, distance determination (from muzzle to target), and the comparison of bullets and cartridges to determine possible sources for firing.
- Fingerprint Analysis: The examination of prints, both visible and latent, left behind from the friction ridge on human skin, typically the fingertips. Many methods are available to visualize prints, including physical, chemical, and through various light sources, allowing them to be photographed and compared.
Digital Evidence: The identification, preservation and analysis of the digital crime scene and the presentation of those results as evidence. The initial focus of the Digital Evidence Unit will be on mobile devices such as mobile phones. The unit will eventually examine seized evidence from a range of devices, including laptops, as well as computers and portable media such as USB sticks, CDs, and DVDs. DEU will offer its services to as many as 40 agencies in the District of Columbia justice system, including the Metropolitan Police Department, U.S. Attorney’s Office and U.S. Capitol Police.
The DFS will be expanding to offer analysis of controlled substances, digital evidence, and documents, as well as photographic analysis.