Mark is briefly introduced in "Saw III" as a detective investigating the scene of Troy's inescapable trap. In "Saw IV" he is placed in a trap as a part of Officer Daniel Rigg's test. However, he is later revealed to be John Kramer's accomplice after he frees himself and leaves Rigg to die. "Saw V" reveals that Hoffman's sister was murdered by her abusive boyfriend, and that Hoffman took revenge by placing him in an inescapable trap made to look like one of John's. John found out about the trap and blackmailed Hoffman into working for him, but Hoffman eventually became a willing apprentice and aided him in nearly every subsequent trap.