FBI chemists analyze unknown powders, liquids, and stains to determine the chemical identity or characteristics. These cases usually involve threat letters, dyes, and tear gases associated with bank dye packs, drug and pharmaceutical analyses, ink analyses, and the analysis of personal lubricants and spermicides in sexual assault cases.
Whether a piece of metal in an exploded bomb or the fragment of a broken weapon, FBI metallurgists analyze metal evidence to learn about its composition and properties. Their work includes analyzing metals that break unexpectedly, such as in a building collapse, or piecing together fragments of weapons.
Paints and Polymers
Paint and polymers experts
- analyze paints, tapes, adhesives, and other polymeric materials for possible fracture matches;
- compare questioned or transferred materials to items of known origin; and
- sourcing of automotive paints, duct tapes, and some vehicle parts to provide investigative leads.
The cases tend to evolve from hit-and-runs, abductions, (attempted) bombings, threat letters, and counterterrorism investigations.
Experts analyze biological samples and food evidence for the presence of poisons and drugs. In addition to FBI field office investigations, FBI toxicology experts support state and local agencies with toxicological examinations.