The forensic pathologist is a subspecialist in pathology whose area of special competence is the examination of persons who die sudden, unexpected or violent death. The forensic pathologist is an expert in determining cause and manner of death. The forensic pathologist is specially trained: to perform autopsies to determine the presence or absence of disease; to interpret injuries and injury patterns; to interpret effects of poisoning; to evaluate historical and law-enforcement investigative information relating to manner of death; to collect medical evidence, such as trace evidence and secretions, and to document evidence of sexual assault. The forensic pathologist must have a working knowledge of other non-medical disciplines, including: toxicology, firearms (wound ballistics), trace evidence, forensic serology and DNA technology. The forensic pathologist acts as the case coordinator for the medical and forensic scientific assessment of a given death, making sure that the appropriate procedures and evidence collection techniques are applied to the body. At death scenes, forensic pathologists bring their expertise to bear upon the interpretation of scene findings, in the assessment of the consistency of witness statements with injuries, and in the interpretation of injury patterns or patterned injuries.