Lawyers suing on behalf of investors of cryptocurrency exchange Binance.com have asked to depose its founder and former CEO Changpeng Zhao before he is sentenced to federal prison.

Zhao, better known as CZ, pleaded guilty last month to federal money-laundering charges. Federal prosecutors raised concerns that Zhao, a billionaire from the United Arab Emirates, was a flight risk. On Thursday, a federal judge in Seattle ordered him to remain in the United States until his sentencing on Feb. 23.