My take on what happened here:
If the claims are true, we had 3 Mystery Roles: Caligno (Cop), Tanz (Something), Quarezha (Something).
Quarezha losing his ability tells me it was a 1-shot role, and it somehow didn't work on Tsukasa. Might've been even a 1-shot Vigilante and Tsukasa got protected by Tanzklaue and he's a Doc, or Tsukasa is a killproof.
If above is true then Mafia's Nightkill was successful and that's what killed Caligno, unless Tsukasa is a Self-Bus Driver and he switched with Caligno and he died from Quarezha's Vig-shot (mafia's nightkill would be blocked by someone then).