I was playing on the 360, so no mods - in the house, planning out which of the guests I would off first.
And then one died. While I was still planning. I was downstairs, heard a spell effect go off - the summon one, I think, oddly enough, and then heard a body hit the ground. I rushed upstairs, to find everyone business as usual - except for the dead Nord.
I looked about for anything weird - and confounded, was eventually forced to conclude it was just an isolated incident.
Shortly after, the remaining guests started dropping like flies. Eventually the dark elf girl was the only one left - so i assumed she had some AI bug and had decided to randomly slaughter everyone. Then she died.
Needless to say, I left the house very quickly, lol, not sure wtf had happened. I got the bonus for the guests not knowing i was the killer - because this time, I wasn't!
I haven't been able to reproduce this - has anyone else had a similar occurence?