Raymond Martinez Fernandez (December 17, 1914 – March 8, 1951) and Martha Jule Beck (May 6, 1920 – March 8, 1951) were an American serial killer couple. They are believed to have killed as many as 20 women during their murderous spree between 1947 and 1949. After their arrest and trial for serial murder in 1949, they became known as "The Lonely Hearts Killers" for meeting their unsuspecting victims through lonely hearts ads. A number of films and television shows are based on this case.