Spoiler warning: Plot and/or ending details follow.
A forensic pathologist is an individual who specializes in determining causes of death by post mortem examination of the deceased.
A forensic pathologist on Tarsus IV was summoned to examine two badly burned bodies following a firefight between followers of former Governor Adrian Kodos and a Starfleet team lead by Lieutenant Commander Gabriel Lorca. The bodies were of Kodos's aide Ian Galloway and another follower, but as Kodos had switched his DNA profile with that of Galloway's in his records, testing showed the body as belonging to Kodos. The bodies had been so badly burned that visual identification was impossible, so Starfleet concluded based on the testing that Kodos was dead. (DSC novel: Drastic Measures)