The return of the programme featuring first-hand accounts by detectives, beginning with Pat Marry reflecting on the 2004 investigation into Joe O’Reilly, the man who murdered his wife, Rachel.

Retired Sergeant Major PJ Higgins of the Defence Forces takes viewers back to the chaotic search in 1983 for kidnapped Quinnsworth executive Don Tidey.

Pat Treacy and Martin Walker recall the murders in September 1992 of Esther McCann and 18-month-old Jessica, who died in a house fire