The Code of the Scarlet (1928)

Assigned to catch a gang of outlaws, officers Bruce Kenton and Paddy Halloran rescue Helen Morgan when her wagon is attacked by the very same gang. Through a ruse, Kenton manages to infiltrate the gang, which is holed up in the lawless community of Caribou Flats. While in the employ of villainous trading post operator Jack Blake, Kenton discovers that Blake is not only the leader of the gang but also the man who murdered Helen's brother.