Yeah, but he had over a year to ask questions. That's hardly a limited time frame.
Maybe. My problem with this reasoning is that Butters and Bob seem to have fundamentally different worries regarding Harry: Bob is worried about the Winter Knight mantle, whereas Butters is worried about Harry coming back from the dead.
She punches Harry in the face and refuses to let him say anything. Up until this point, we have been asked to understand Murphy's negative behavior towards Dresden as being the result of her being a good cop, and Dresden doing things that a good cop would object to. Punching suspects, however, is not being a good cop--it is police brutality. And not letting Dresden say anything is just being a stupid cop--he might have been confessing, considering how upset he was. And understanding Murphy's treatment of Dresden as not actually being a result of her being a good cop and caring about the law makes her, in my opinion, a character that's much harder to empathize with and not dislike.
Actually, The time frame is far more limited than what appears on the surface. Butters need to ask the question and gotten a satisfactory answer within a limited time after end of book 14. The more time lapse the more suspicion has time to sets in. If suspicion sets into deep, even the right explanation won't work anymore. Since the book don't show us, I don't really know how long Butters could stay positive about Harry after end of SG. Would Butters accept the explanation if he get the information 3 months after end of CD? or ist it 6 months? or 1 month is already too long.
And I don't think Butters is hankering about Harry coming back from the dead. He is more worried about Harry is not Harry anymore. He accuse Harry of becoming more and more like the fae for example. Bob is dead certain that it will only be a matter of time for Harry to turn into Lloyd Slate version 2.0, so if Butters has been listening to Bob all this time. Well the result is evident.
As for FM Murphy. It should be remembered that at the end of SF, there are rumors running around that Harry has become Marcone's henchman and the fall of Victor Sells and the three eye drug, is Harry acting on Marcone orders.
At the start of book 2, Harry has been losing income since SI has not been calling him for a job lately. When Murphy appear to ask Harry for help, she explain that the above rumor has cause some pressure in the police force. If not for Murphy standing up for Harry, it is likely that Harry is already captured by the police.
Before the event in Mcfinn house, in which that girl, I forgot her name, is found dead. Marcone visits Harry. It makes it look a lot like Harry is taking Marcone's orders.
This and that circle diagram Murphy found in Mac's bar.
You can see that Murphy has been getting wave after wave of circumstancial evidence that suggest Harry is the bad guy. It is not in FM only, the trust between Harry and Murphy has been put to the test since end of SF. Considering that the level of trust between the 2 is still relatively new and not as strong as say in book 6 or book 10, for Murphy to give Harry that much leeway is already good enough. When that trust is seemingly betrayed, Murphy obviously blew up.
Of course, she is proven wrong in the end, and she apologize for it. But the fact that she punch Harry is quite understandable at the time. Well, perhaps she should not go so far as doing physical violence, but I think her anger and disappointment is understandable.