Italian authorities are questioning 12 leaders from a hardcore section of Juventus' supporter base over a string of alleged offences.
Among the accusations is one of making illegal demands to the Bianconeri, with the ultras group threatening to start racist chanting at the Allianz Stadium if the club refused to give them more than their allotted number of tickets for fixtures.
Other charges levelled at the Juve fans include criminal association, money laundering, extortion and violence.
Sky Sports report that the investigation is linked to claims of infiltration by a local crime mob, who are alleged to have taken power in the ultras section.