When former semi-pro hockey player Thomas Clayton found his wife, Kelley Clayton, murdered in their New York home one night after a late poker game, he called 911 in distress. But as police investigated, they discovered evidence calling Thomas’s motives into question and sensed something more sinister at play. “20/20” co-anchor Deborah Roberts reports on the twisted plot behind the gruesome murder of the mother of two, Kelley Clayton, and how her 7-year-old daughter was the sole witness to the