Very rarely shown, I was fortunate to have seen it at its release.
Several dozen onlookers witness a daring gang murder, but only LA businessman Fred Morrow agrees to testify. His family is tormented by the youthful thugs, the police being unable to protect them from the gang's attacks and ever increasing violence. Will Morrow hang tough and perform his civic duty or will he recognize his mistake and develop amnesia, thereby allowing one of B-movie Hollywood's most brazen killers to go free? The theme music ("Ruby Duby Du"), written by Charles Wolcott, is absolutely haunting, and is far and away my favorite instrumental.
Jeffrey Hunter, Dennis Hopper, Pat Crowley, Johnny Nash and Susan Harrison make for a top-notch cast.
Four years after its release I met a person who likewise considered "Key Witness" his favorite movie. Forty-two years later we remain best friends.