The Case of the Violent Suitor - S1.E25

"Aunt Lottie", an advice columnist who is actually a man named Alex Doogle, advises a young woman to break up with her violent and insanely jealous boyfriend. The jilted boyfriend then finds Doogle, severely beats him and threatens his life. Doogle turns to Sherlock Holmes, both for his own protection and to save the young woman from her crazed fiancé.