Andrew Waldron

A young man inherits a mansion in a Florida swamp from an uncle he never knew he had. When he, his assistant and the estate's executor arrive at the house, the audience catches sight of someone crawling in the window, though the house is supposed to be unoccupied. As the house staff begins to arrive they sense a strange presence in the house, and when a young woman no one knows runs into the house to escape a knife-wielding psycho, the occupants realize they may be in danger... (imdb)

Hearing his brother the Express Clerk is in trouble, Bob Williams rides to the Express Office only to find the safe open, his brother and the money missing, and himself accused of the robbery. To clear himself he trails and finds the outlaws engaging them in a fight. But during the melee, the gang leader double-crosses his men and sneaks away with the money and Bob now has to catch him. (imdb)

Jack is after the mysterious murderer who killed his father and brother. The only clue is the Ace of Clubs pinned to their bodies.