[Let's say they're still in costume, because it's funnier. Anyway, she appreciates his approach, being all business about it.]

There was a struggle near the fountain. A little blood, a little water disturbed, but nothing too terrible. And then the demon was brought directly to the ballroom, where they were killed with the precise tools needed to kill them.

Given that, I think it looks like an ambush on the demon by someone who came prepared.