Forensic science is an important part of the criminal justice system, in both state and federal courts. Forensic scientists examine and analyze evidence from crime scenes and other relevant locations to develop objective findings that may assist in the investigation and prosecution of criminals, or clear an innocent person from suspicion.

Common forensic science laboratory disciplines include (1) forensic molecular biology (DNA); (2) forensic chemistry; (3) trace evidence examination (hairs, fibers, paints, polymers, glass, soil, etc.); (4) latent fingerprint examination; (5) firearms and toolmarks examination; (6) handwriting analysis; (7) fire and explosives examinations; (8) forensic toxicology; and (9) digital evidence.

Practitioners of these forensic science disciplines are usually found in medical examiner or coroner’s offices, universities, and private practices. And the United States Department of Justice maintains forensic laboratories at (1) the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF); (2) the Drug Enforcement Administration (DEA); and the Federal Bureau of Investigation (FBI).

In New Hampshire, forensic science plays a crucial role in the criminal justice system, aiding in the investigation and prosecution of crimes as well as exonerating the innocent. The state adheres to both state statutes and federal law regarding the use of forensic evidence in court. Forensic scientists in NH may work in various settings, including state crime labs, medical examiner offices, universities, or private practices. They specialize in disciplines such as DNA analysis, forensic chemistry, trace evidence, fingerprinting, ballistics, handwriting, fire and explosives investigation, toxicology, and digital evidence. New Hampshire's forensic laboratories operate under strict guidelines to ensure the accuracy and reliability of evidence. At the federal level, agencies like the ATF, DEA, and FBI maintain their own forensic labs, which can collaborate with state authorities on criminal cases. The admissibility of forensic evidence in NH courts is subject to the rules of evidence, which include considerations for scientific validity and expert witness testimony.