American Serial Killer – Original Artwork - John Wayne Gacy (1942-1994) ‘Blue Moon Calm’ Oil Painting – J.W. Gacy to the front and signed to the reverse, oil on canvas, measures 40.6x50.8cm. Note: John Wayne Gacy was an American serial killer who sexually assaulted, tortured and murdered at least 33 teenaged boys and young men between 1972 and 1978.