The Wakefield Case (1921)

A playwright, Wakefield, Jr., turns detective when his father is killed after nearly capturing two brothers in possession of four rubies belonging to the British Museum. An investigation suggests that "the Breen girl" is responsible for Wakefield's death, and the younger Wakefield pursues her across the ocean to the United States. The true identity of several characters, including the robbers and the girl, is in constant question, but Wakefield finally gets to the culprits; solves his case; and learns that Ruth Gregg, with whom he has fallen in love, is not only "the Breen girl," but actually was posing as a gang member for the Secret Service.