Sometimes Aunt Martha Does Dreadful Things (1971)

Stanley and Paul, a pair of friends on the run from the law, rent a house in the suburbs, where they decide the best way to lay low is for Paul to dress as a woman and pretend to be Stanley's Aunt Martha. Not too long after the pair move into their new home, Paul suddenly murders a young woman Stanley brings home with him. Paul's violent tendencies continue to spin out of control, and soon nobody who comes near is safe from him.