How was Douglas killed? With what?

Douglas was shot in the head

“That was in the inclosed official report. It didn’t say ‘horrible’: that’s not a recognized official term. It gave the name John Douglas. It mentioned that his injuries had been in the head, from the discharge of a shotgun.

One glance at the victim was enough to show the healer that his presence could be dispensed with. The man had been horribly injured. Lying across his chest was a curious weapon, a shotgun with the barrel sawed off a foot in front of the triggers. It was clear that this had been fired at close range and that he had received the whole charge in the face, blowing his head almost to pieces. The triggers had been wired together, so as to make the simultaneous discharge more destructive.