You Can’t Beat the Law (1928)

Jerry Judd, a young cop, is on the trail of a gang of stick-up men who rob jewelry stores. He falls in love with Patricia Barry, who it turns out is the sister of the gang's leader, Blackie. She loves Jerry, too, but is torn between her love for him and her loyalty to her brother, and is put to the test when Jerry gets closer to discovering where the gang's hideout is.