Baretta: The Dippers (1976)

Synopsis
A young pickpocket who works in a major airline terminal is found brutally murdered. Undercover cop Tony Baretta (Robert Blake) can't understand why anyone would have reason to bump off a two-bit thief. But he intends to find out, and to do that he poses as an experienced "dip." Sanford and Son regular Whitman Mayo appears in a key supporting role. ~ Hal Erickson, All Movie Guide