To lethally eliminate Campbell, you can confront him directly in his office or ambush him. For a non-lethal approach, you need to find the Heretic's Brand, located in the kennel area. Once you have it, you must lure Campbell to the interrogation chair in the secret room beneath his office. This often involves knocking him out and carrying him. Be careful of his bodyguard, Captain Curnow, who can also be dealt with lethally or non-lethally. The non-lethal option for Curnow involves separating him from Campbell.
