A Daughter of the Law (S)

Early in the prohibition era, a girl Internal Revenue officer goes into the hill country to find out how they are making and transporting Moonshine. She pretends to be a tourist, interested in painting pictures of the local scene, and gets a bed in the home of an old woman and her grown son, whom it turns out, is the one moving the illegal booze. He has a novel way of doing it so the government is unable to detect it- inside his motorcycle. The girl finds out, but she is exposed before she can escape.