In a Moment of Passion on AllMovie

A cut-rate actor tires of trying to boost his career through normal channels and so decides to murder his way to the top in this lurid melodrama. Stand-in Victor Brandt, starts out by killing the rising international star Werner Soehnen during the filming of a historical romance. Sure enough, he gets the lead and ends up on a European estate learning horseback riding tricks from stunt coordinator/aspiring actress Tammy Brandon. She is angry that the part she was to play in the film was stolen by the pill-popping blonde, Crista Kelly. Victor is attracted to Tammy, and simultaneously woos her while continuing to murder the producer and his girl friend. Meanwhile, the mistress of the estate, Greta begins to suspect that something is horribly amiss with Victor. She tries to warn Tammy, but Tammy, thinking that lesbian Greta is only saying this out of jealousy, disbelieves her. Poor Greta doesn't live too long after that. Eventually Crista arrives and is immediately suspicious of the recent deaths. This suspicion leads Victor to tell Tammy the truth, leaving her to decide whether to join or stop his killing spree.