A Blueprint for Murder is a 1953 American film noir thriller directed and written by Andrew L. Stone and starring Joseph Cotten, Jean Peters and Gary Merrill.

[1] Whitney "Cam" Cameron arrives at a hospital and learns that Polly, the stepdaughter of his widowed sister-in-law Lynne, is suffering violent convulsions resulting from an unknown illness.

Amateur sleuth Maggie, the wife of Cam's lawyer Fred, notices the similarities between Polly's symptoms and those of victims of strychnine poisoning about whom she has read.

Fred reveals that Cam's brother's will bequeaths his large fortune to Lynne only in the event that both of his children die, providing her with a credible motive for killing her husband and Polly.

In a contemporary review for The New York Times, critic Howard Thompson wrote:While supposedly based on fact, the rhetorical contrivances of this lengthy Twentieth Century-Fox item defeat a trim little cast headed by Joseph Cotten and Jean Peters, and offers a few bursts of suspense and a fairly provocative story blueprint, the stalking of a beautiful poison expert.

Indeed it loses conviction altogether before the climax, when he traps the culprit aboard an ocean liner, squiring her intended victim and enough strychnine—as Mr. Cotten accuses her, twice—to choke a horse.