The Lone Ranger (1949)

S1E45 Trouble for Tonto

In order to gather proof of the Buck Fargo gang's scheme to rob the Baxter bank, Tonto takes on the guise of Black Eagle, who has supposedly aided in the kidnapping of Terry Baxter after Black Eagle's death. However, Tonto's disguise is compromised when a ring belonging to Black Eagle's squaw exposes the truth.