Paranoiac is a 1963 British suspense film from Hammer Films directed by Freddie Francis and starring Janette Scott, Oliver Reed, Sheila Burrell, and Alexander Davion. The screenplay was written by Jimmy Sangster, based loosely on the 1949 crime novel, Brat Farrar by Josephine Tey.
A mysterious man, first sighted by Eleanor, appears who greatly resembles the dead brother. Eight years earlier, when Tony was a youth, he had left a suicide note and had apparently jumped off a seacoast cliff, but his body had never been recovered. Now, the new Tony appears, claiming that he had simply run off. Eleanor wants to believe that the man is Tony. Harriet Ashby Burrell, their Aunt, is immediately hostile and calls the man an impostor. Simon appears to be more openminded about the situation. Desperate to keep his hands on the family money, Simon sabotages the car brakes and Eleanor and Tony are nearly killed, saved only by Tonys quick thinking. Eleanor finds she is falling in love with her supposed brother. Overcome with conflict over her seemingly incestuous thoughts, she is about to commit suicide, when the man restrains her and confesses that he is not her brother Tony, but instead is a con man hired by the embezzling Keith Kossett Bonney, son of the family attorney Denham.Meanwhile, Simon has been having an affair with Eleanors nurse, a French woman. When she realizes what Simon is up to, she decides to leave but Simon drowns her in a nearby pond. Simon tells Eleanor that the nurse has simply left. ........
Source: Wikipedia