Really good movie, suspenseful with a lot of plot twists and turns.

Through a series of elaborate schemes, a wealthy woman arranges for the murder of her husband's mistress and then takes steps so that the crime won't be traced back to her. The detective investigating the murder soon realizes her role in it, and sets out to find a way to pin the murder on her.

Directed by Marvin J. Chomsky
Starring Cybill Shepherd, Ken Olin, Christopher McDonald