FORENSIC GEOLOGY AT THE FBI: WHY DOES THE FBI NEED A GEOLOGIST?

The Federal Bureau of Investigation employs three geologists in the mineralogy group of the FBI Laboratory's Trace Evidence Unit. The mineralogy group receives, processes, and examines geologic trace materials recovered as physical evidence. The analysis of geologic materials can be used to compare items to determine the existence of a shared origin, for identification, and to ascertain provenance.

Any law enforcement agency can submit evidence to the FBI Laboratory, resulting in a broad range of examinations. Items examined by the mineralogy group include soil, minerals, rocks, gemstones, glass, and building materials. The majority of casework, however involves the examination and comparison of questioned and known samples of soil or glass. Soil examinations include the comparison of color, texture, and mineralogy. Glass examinations include the comparison of physical, optical, and chemical properties. Instruments utilized in typical casework include the stereobinocular, petrographic, and phase contrast microscopes, the Glass Refractive Index Measuring system, the X ray Diffractometer, and the Inductively Coupled Plasma Optical Emission Spectrometer. Constraints on analytical latitude at the FBI include the necessity to adhere to documented procedures and QA/QC protocols, conforming to the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB) accreditation standards, and the pressures of time-sensitive deadlines.

In addition to casework, FBI geologists provide expert testimony in legal proceedings, support on-going field investigations, train the law enforcement community, and develop and implement new technologies to enhance scientific examinations. The mineralogy group has collaborated on casework and research with the Smithsonian Institution, the U.S. Geological Survey, Germany's Bundeskriminalamt Kriminaltechnisches Institut, and the European Network of Forensic Science Institutes.