Mark tells the story of a man called Joe Fenton and how he was connected to Stakeknife. We learn there was a hierarchy of agents, where some were saved and some were not.

Reporter: Mark Horgan
Produced and written by: Mark Horgan and Ciarán Cassidy
Co-Producer: Paddy Fee
Editing and Sound Design: Ciarán Cassidy
Composer: Michael Fleming
Sound mixing: Ger McDonnell
Theme tune by Lankum
Artwork by Conor Merriman
Assistant Commissioners for BBC: Lorraine Okuefuna and Sarah Green.
Commissioning Editor for BBC: Dylan Haskins