Amanda Knox, along with NXIVM members, signed a petition demanding prosecutors answer questions about Raniere's case.

NXIVM leader Keith Raniere is already facing sex-trafficking and other charges, alongside five other people.

"As alleged, Keith Raniere displayed a disgusting abuse of power in his efforts to denigrate and manipulate women he considered his sex slaves," said an assistant director-in-charge of the FBI's New York field office.