Forensic scientists apply scientific knowledge and skills to investigate crimes. the information they provide may help the police to find or eliminate a suspect in a crime. Forensic scientists usually specialize in one area of forensics, such as Dna analysis, firearms examination, or toxicology. the service that forensic analysts provide is invaluable in police and legal work, and their expertise is called upon to detect traces or confirm the presence of substances such as poison, drugs and alcohol, in the human body at postmortems.