A Forensic Pathologist, first and foremost, is a physician. More specifically, a Forensic Pathologist is a medical doctor who is specially trained to perform autopsies, investigate suspicious deaths, and determine how, and by what means, a person died (cause and manner of death, respectively).
To become a forensic pathologist, one must achieve a Medical Degree (M.D.), then complete 4 to 5 years of training in general Pathology, and 1 to 2 years of specialized training in Forensic Pathology.