Robert Spangler (January 10, 1933 – August 5, 2001) was a serial killer who murdered his first wife, son, daughter, and his third wife. On the morning of December 30, 1978, in Arapahoe County, Colorado, Robert Spangler lured his wife, Nancy, into the basement with the promise of a "surprise" and shot her in the head with a revolver. Going upstairs, he shot his teenage children, Susan and David; David was slow in dying, so Spangler smothered him with a pillow. Spangler then altered the scene to make it appear that his wife had shot their children and then herself. On April 11, 1993, after Spangler's third marriage to 58-year-old aerobics instructor Donna Sundling went sour, he took her hiking in the Grand Canyon and pushed her off a 140-foot (40 m) drop to her death.