You was calmly doing your things at home as you gear knocking at your door, as soon as you ask who it is, you hear " Kamisato Ayato - that's police, please open the door", and as soon as you open it you see him.. " I am very sorry but yesterday there was another killing, as you already know probably, in your neighborhood.. Can you go with me to the police office for a small interrogation?" You can't decline, you don't want to be suspicious in any way, you are clean after all, or.. maybe not