The Newman Shame (1978)

John Brandy is an ex-cop on holiday in Singapore with his girlfriend Ginger when he hears an old Perth banker friend of his, Frank Newman, has committed suicide. He travels to Perth and discovers that Newman killed himself after being drugged at a party and found himself in a pornographic film; he was blackmailed and embezzled money to pay off his tormentors, but when the film was distributed anyway he decided to take his own life. Newman and Ginger decide to investigate who is behind the blackmail racket.