Whitney Cameron is in a quandary: he's attracted to his beautiful sister-in-law, Lynn, but also harbors serious suspicions about her. Her husband, Cameron's brother, died under mysterious circumstances, and now that the death of her stepchild, Polly, has been attributed to poisoning, he suspects that Lynn is after his late brother's estate, and killing everyone in her way.
Jack Kruschen
Harold Y. Cole

Barney Phillips
Detective Captain Pringle
Freddy Ridgeway
Doug Cameron

Harry Carter
Wheeler (uncredited)