Forensic science is the use of science as it applies to the legal system and as science is used to solve crimes. Forensic scientists use their knowledge of science to help determine the facts and the truth in both civil and criminal matters. A criminalist examines and interprets physical evidence. An odontologist is a dentist who applies the principles of dentistry to identify human remains and bite marks. A pathologist is a medical doctor who determines the cause of death by performing an autopsy. A forensic engineer is someone who has been trained as an engineer and who applies engineering concepts in legal situations. A ballistic analyst examines guns and ammunition and uses his or her expertise to interpret gunshot wounds. A serologist is a medical specialist who identifies and examines blood and other body fluids. A psychiatrist is a medical doctor with an advanced degree in psychiatry.