Miss Pinkerton (1932)

Scion of the once-rich Mitchell family, Herbert Wynn is found shot to death. Nurse Adams, bored by hospital routine, is recruited by the police to ferret out clues as she tends to Wynn's elderly aunt Julia. Jokingly given the 'rank' of Miss Pinkerton, after the famous detective agency, Adams probes into the mystery, but not before a second death.