Blackout (1950)

A man suffering from temporary blindness accidentally walks into a house where a murder has just occurred. The killers, realizing he's blind, decide not to kill him but just knock him out and leave him out on the street. When the police find him they don't believe his story because they can't find a body. After he regains his sight he sets out to find the body and the killers, and runs into a woman who is looking for her missing brother, who may or may not be the murder victim.