Lure of the Wasteland (1939)

Federal agent Smitty assists Butch Cooper, leader of a gang that robbed a train in which the loot was never recovered, in making an escape and accompanies him to the Utah badlands. Parker, leader of a gang of cattle rustlers, recognizes Butch. The latter takes Smitty to the spot where the loot was buried, but it has disappeared. Butch suspects his former comrades of making off with the money. Smitty and Butch have acquired jobs on a nearby ranch and Cookie, a former gang member, is questioned about the missing money. Butch encounters two members of his old gang and they take him to Parker. Both suspect the other of having the money, but they finally conclude that Cookie either has it or knows where it is. They kidnap him and he confesses he dug up the money and it is in the safe at the ranch of Judge Carlton. Smitty comes in and, in the struggle that follows, is revealed as a federal agent working undercover. He is left guarded while Butch, Parker and the gang ride to Carlton's ranch.