Deathtrap is a 1982 thriller based on Ira Levins play of the same name, directed by Sidney Lumet from a screenplay by Levin and Jay Presson Allen, starring Michael Caine, Dyan Cannon and Christopher Reeve. Critics gave the film mostly favorable reviews while noting its plot similarities to Caines 1972 film Sleuth.
Clifford Reeve arrives by train. Myra tries desperately over the course of an evening to convince Sidney to work with Clifford as equal partners, but to no avail Sidney attacks Clifford, strangling him with a chain. Sidney removes the body but still has to convince Myra to conspire with him. She reveals nothing when they receive an unexpected visit from the psychic Helga Ten Dorp Irene Worth, a minor celebrity who is staying with the Bruhls neighbors. Helga senses pain and death in the house before she leaves she warns Sidney about a man in boots who will attack him.As she prepares for bed, Myra is beginning to come to terms with what Sidney has done. All is calm until Clifford bursts through the bedroom window and beats Sidney with a log. Clifford chases Myra through the house until her weak heart gives out she collapses and dies. Sidney calmly descends the stairs, uninjured, and sidles unperturbed to Cliffords side. They exchange a few words about what to do with Myras body, then exchange a passionate kiss. ........
Source: Wikipedia