TAMPA, Fla. (AP) — A Florida teen identified as the mastermind of a scheme that gained control of Twitter accounts of prominent politicians, celebrities and technology moguls pleaded not guilty Tuesday to multiple counts of fraud.

Graham Ivan Clark, 17, is accused of using the hijacked Twitter accounts to scam people around the world out of more than $100,000 in Bitcoin.

He is charged with 17 counts of communications fraud, 11 counts of fraudulent use of personal information, and one count each of organized fraud of more than $5,000 and accessing computers or electronic devices without authority. The brief hearing in Tampa took place via the video conferencing service Zoom.

Clark is scheduled for a bond hearing today. He remains in the Hillsborough County Jail with bail set at $725,000, according to court records.

Clark was arrested on Friday in Tampa, and the Hillsborough State Attorney’s Office is prosecuting him as an adult, a news release said.

Two other men were also charged in the case. Mason Sheppard, 19, of Bognor Regis, U.K., and Nima Fazeli, 22, of Orlando were charged separately last week in California federal court.