Bonanza: S2 E3 - Badge Without Honor Bonanza

After a U.S. deputy marshal apparently saves Adam's life by gunning down two men who shot at him, he eventually reveals that he in town to bring a close friend of the Cartwrights to San Francisco to testify in a statewide racketeering trial, but the Deputy Marshal's motives soon become suspect as to what he really want to do with the reluctant witness.