Episode 412, "Knuckle Up" Tomorrow 12|11c
SEASON 1, EPISODE 114 - Rush and Valens reopen the unsolved killing of Arnold Collier (Lyndon Smith), a 6-year-old orphan who died in an empty field in 1958. The former orphanage where Arnold lived now operates as a day care center. The two detectives interview several nuns who still work in the building. The investigative team locates the boy's now-adult sister, Gretchen (Molly Cheek), who was sent to the orphanage with her brother when their parents died in a car accident. After further investigation, Rush and Valens realize that Arnold's records were falsified, and they soon discover that the identity of Arnold's mother could lead to the killer.