John Needham's Double.

Although he has been appointed to guard the fortune of young Thomas Creighton, the unscrupulous Lord John Needham decides to spend all of it after Tom runs away. Then, however, an announcement comes that Tom is returning and that he plans to claim his money. Fearful of punishment, both from Tom and the authorities, John kills his cousin and exact double, Joseph Norbury, and takes Joseph's place, thereby making it seem as if the dead man is really John.