Sigmund "Seymour" Magoon (April 21, 1908[1] – after 1950), known as "Blue Jaw", was an American hitman in New York's Murder, Inc. gang, one of many members who were implicated by the testimony of former member and government informant Abe "Kid Twist" Reles.
A longtime member of Murder, Inc., Magoon was heavily involved in the painters' unions with Martin "Buggsy" Goldstein during the 1920s and 1930s. Magoon helped testify against the other members of Murder, Inc., along with Albert "Tick Tock" Tannenbaum and Sholem Bernstein.
He married Lillian Smolensky in 1933. He was a fish wholesaler in Chicago in 1950.[2]