Not every death warranted investigation by a coroner or medical examiner, but you might find files on ancestors who perished in accidents, suicides or crimes. These files might prove scant or cryptic, or could include photos, depositions and the sort of evidence you’d expect on an episode of “CSI.”
Places to inquire after such records, besides the coroner’s or medical examiner’s office in the county where the death occurred, include the county clerk’s office, probate files for the deceased’s estate, and justice of the peace files. The oldest records may have been transferred to a state archive or library or university repository. (For example, the University of Pittsburgh has Allegheny County coroner files from 1887 to 1973.) These files may be restricted to members of the deceased’s immediate family.
The Family History Library has a few microfilmed coroners’ records and indexes, which you can find with a keyword search for coroner. Some county USGenWeb sites have transcriptions or summaries of local coroners’ records, as does the San Francisco Genealogy site.