The main interrogation scene is played out in the garage owned by production assistant Mark Scullion. Liam O'Riordan was tied to the chair for 3 hours.
To get a better feel of how a serial killer (Griffin) and a Criminal Profiler (Detective Booth) would communicate with each other, Carl Thomason consulted with graduates of Criminal Behaviour and Criminology as he wrote the screenplay.
Levi Day was not present for the original office meeting scene, he was filmed separately to John Brimm and Sam Kubrick and edited in with them.
Aaron Raw shot only the interior garage scenes using a tripod. The rest of the film was shot by Carl Thomason all hand-held. This was done to give both sides of the film a different feel; more methodical for the garage scenes and a coarser feel for the rest of the film around it.