Five-year-old Siobhan McGuinness was walking home in Missoula, Montana in February of 1974. The distance was very short, but just long enough for a killer to find her. After more than 45 years, that killer (since deceased) has now been identified through a familial DNA hit. Richard William Davis had no ties to Siobhan or the community. Could the solving of her case bring the same closure for others throughout the country? Law enforcement and her family hope so.