Tombstone Territory (1957)

S3E3 The Hidden Gunman

Hollister discovers Anita Torison in possession of illicit jewels and takes her aboard a stagecoach heading to Tucson under a warrant. Along the journey, a troubling event at a way station piques his curiosity, prompting him to uncover the identity of Boone Cahill, her secret partner in crime, hidden among the other passengers.