Eventually:

"So - there's an unwarded box in his house. You can walk me there, presumably in the middle of the night would be best? I grab his amulet, we all three walk out, Fire refuses to talk to the police except when the truth sounds supportive of my 'inherited from my great aunt' story and has his halo turned way down so he doesn't match the description - he does not attract attention in the form of obvious-to-other-humans association with you or by being generally oddly-behaved, at least until the case is abandoned - you think this works? You think Fire will cooperate without me having to actually use anything other than university-minimum on his amulet?"