Funny coincidence I'm just replaying Fallout 4 and just yesterday I followed a "mysterious signal" to the New England Technocrat Society, where all members had been killed and turned into Ghouls. What happened was that they got an AI to run the building and the AI was then aggressively trained on Horror movies etc. to prepare it to organise the upcoming Halloween party, and it decided that death and torture is what humans liked.

This seems awfully close to the same sort of scenario.