(OBVIOUS SPOILERS) It's not Crane, here's why:
The killer isn't Crane, he is clearly being set up by a person wearing a glamour. Who would photograph themselves and not disturb the evidence of a crime scene and then leave the photos, literally in an envelope for Bigby to find?
I'm not certain if Crane did the prostitution thing (seems likely enough though), but I am certain he isn't the killer.
TL:DR I think Crane is heavily involved in obstructing the investigation (I think he hired Dee and Dum) in order to save his own ass (he'll get kicked out of his office if anyone found out he was using Fabletown taxes and time to pay for prostitutes, and sickly glamoured ones at that), but he isn't the killer.
Who agree's, who objects, anyone want to add any evidence for or against Crane being the killer or obstructing the investigation to protect himself from a scandal?