Another Man's Poison 1951

Mystery novelist Janet Frobisher, lives in an isolated house, having been separated for years from her criminal husband. She has fallen in love with her secretary's fiancé and when her estranged husband unexpectedly returns, Janet poisons him, but just as she's about to dispose of the body, one of her husband's criminal cohorts also shows up.

Cast:

Bette Davis
Janet Frobisher 

Gary Merrill
George Bates 

Emlyn Williams
Dr. Henderson 

Anthony Steel
Larry Stevens 

Barbara Murray
Chris Dale 

Reginald Beckwith
Mr. Bigley