Hoffman, who had been investigating the Jigsaw killer, set Seth up in a Jigsaw style trap of his own, one that Seth couldn't win. It killed him (2008's Saw V). ... Eventually, Hoffman became Kramer's apprentice after they both realized how similarly their interests were aligned.

How did Hoffman Join Jigsaw?

Strahm began to pursue Hoffman as a five-person trap set up by the latter played out. Hoffman planted evidence to frame Strahm as the last Jigsaw apprentice. This deception eventually led Strahm's superior, FBI Agent Dan Erickson, to put out an all-points bulletin for Strahm's immediate arrest for the Jigsaw murders.

Why did Dr Gordon help Jigsaw?

Doctor Lawrence Gordon M.D. is the doctor who diagnosed John Kramer's cancer and was initially a suspect in the Jigsaw case. ... He was put through a test to prove his respect for life, after John found out he was cold, uncaring, and unfaithful to Alison, his wife.