Anatomy of a Crime (movie, 1969)

Private detective David Ross has two apparently unconnected cases to investigate in the same day. In the first he is hired by a millionaire who paid a large ransom for his kidnapped daughter twelve years before, but she was never seen again. Now a woman has come forward who claims the young girl she raised is the millionaire's missing daughter. Later, Ross is contacted by a retired burlesque dancer who's about to publish her memoirs and possibly reveal the secrets of some important people, but someone is determined to stop her.