A Blueprint for Murder

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

Cam has great affection for his young nephew Doug Freddy Ridgeway. He begins to fear for the boys life when Maggie Sargent Catherine McLeod, the wife of his lawyer, Fred Gary Merrill, mentions that the dead girls symptoms sound suspiciously as if she had been poisoned.Fred reveals that the will of Cams brother, who also died from unspecified causes, put all money into a trust for the boy. Lynne would inherit it all if anything happens to Doug. ........

Source: Wikipedia