Not saying the BJ is going entirely based on the CDC Mafia considering he may be taking queues from games played on MU but this is on the wikia's list of roles. https://cdcmafia.fandom.com/wiki/CDC_Mafia_Rulebook#Roles
Given how early they got to Tanev, and other TP specials, it's likely Jazz did have investigative powers as Kingpin. And the roleblocker is likely the lackey who shows town upon investigation.
So even our confirmed TP could be the role blocker