Rocky Lane Western #62 (1954)

Rocky Lane and Black Jack investigate the murder of Hank Kirby, who has been locked up in jail. When Kirby's gun is found near a dead man, Rocky must clear his name and catch the real killer, eventually mailing evidence to the chief marshal to prove Kirby's innocence before he can be hanged. The story involves a scheme for Kirby to escape across the border to Canada while the truth catches up with him.