The Boy in the Box (S01E14)

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. (Warner Bros. UK)