Amku was killed by the Crusader.
There were no killings by the Mafia because Neyra was blocked, and Amku was killed.
It's said that Amku wasn't from around here, which could be evidence that he was from some kind of Mafia. Or rather, not an angel.
I suggest we execute Neyra.
Alternatively, we could try to solve the clue and hang the werewolf.

Барон "Vampires"
Отдай свои прошлые сны,
В сомненьях себя обрети,
В бешеном танце душа кружится!
Не думай, что будет потом,
Здесь и сейчас мы живем,
Стань хоть на миг сам собой, слышишь!