Dark Mirror (1984)

After attorney Frank Girard is murdered Detective Al Church suspects that Ms Leigh Cullen is the perpetrator as she was supposedly last seen with the man However after Leighs alleged twin sister Tracy shows up at the police lineup with Leigh Church is left puzzled and with no specific suspect to pinpoint Therefore Church asks Psychiatrist Dr Jim Eiseley an acquaintance of Leighs to evaluate the sisters and run tests on them in hopes of filtering out the murderer However Eiseleys increasing involvement with Leigh complicates things with Tracy in the picture