FTX co-founder Sam Bankman-Fried is accused of committing a major financial fraud in U.S. history.
A federal judge revoked Bankman-Fried's bail due to probable cause that he attempted to tamper with witnesses.
Bankman-Fried's lawyers filed an appeal against the bail revocation decision.
Prosecutors allege that Bankman-Fried violated several conditions, including contacting potential witnesses and using a virtual private network to evade monitoring.
Former FTX executive Caroline Ellison, Bankman-Fried's ex-girlfriend, plans to testify against him after taking a plea deal.
The judge sided with prosecutors, claiming that Bankman-Fried leaked Ellison's personal documents to the New York Times.
Bankman-Fried's defense argues that he has the right to defend his reputation in the press and needs regular access to a computer and the internet due to the complexity of his defense.
Bankman-Fried, 31, has pleaded not guilty to conspiracy and fraud charges, with a trial scheduled for October.
Prosecutors have accused Bankman-Fried of stealing deposits from FTX to finance risky bets at his crypto hedge fund, funnel contributions to American politicians, and maintain a luxury lifestyle.