Two of a Kind is a 1951 film noir directed by Henry Levin, and written by James Edward Grant, James Gunn, and Lawrence Kimble. The film features Edmond OBrien, Lizabeth Scott, Alexander Knox and Terry Moore.
When the old man refuses to change his will, Mailer decides to kill them, and Kirby plays along. Farrell refuses to assist, and Mailer plans to kill him too. After a botched attempt, with Kirbys help, Farrell exposes the scam to the old man, dooming Mailers plan, and allowing Kirby and Farrell to unite, as Two of a Kind.
Source: Wikipedia