Rio Rattler is a 1935 American Western film directed by Bernard B. Ray.
A dying Marshal gives his identification papers to Tom. After Tom arrives in town, the papers drop and are found during a fight so Tom decides to assume the Marshal's identity. Mason, the chief, now sends Rattler, the killer of the Marshal, to also kill Tom. But when he overhears Tom is a fake, they change their plans and now go to arrest Tom for the murder of the Marshal.