Prosecutors Ask Judge to Tighten Bail Conditions on Sam Bankman-Fried

Federal prosecutors in Manhattan said on Friday that the disgraced cryptocurrency executive Sam Bankman-Fried had tried to contact a potential witness in his criminal case, and they asked a judge to impose new bail conditions limiting his ability to communicate with former colleagues.

In a court filing, the U.S. attorney’s office for the Southern District of New York said Mr. Bankman-Fried sent messages over email and the encrypted messaging app Signal this month to the general counsel of the U.S. arm of FTX, the cryptocurrency exchange he founded. Mr. Bankman-Fried, 30, has been charged with fraud, money laundering and campaign finance violations linked to the implosion of FTX last year.

The communication was “suggestive of an effort to influence Witness-1’s potential testimony,” the filing said. “This is particularly concerning given that the defendant is aware that Witness-1 has information that would tend to inculpate the defendant.”

Prosecutors asked Judge Lewis A. Kaplan, who is overseeing Mr. Bankman-Fried’s case, to prohibit the entrepreneur from contacting current and former FTX employees or using Signal or other encrypted apps to communicate.

A spokesman for Mr. Bankman-Fried did not immediately respond to a request for comment.

Mr. Bankman-Fried built FTX into one of the biggest cryptocurrency exchanges in the world before the company filed for bankruptcy in November. He was arrested in December at his home in the Bahamas, where FTX was based, and then extradited to the United States to face the criminal charges. Judge Kaplan granted him bail under highly restrictive conditions, confining him to his parents’ home near the campus of Stanford University in Northern California.

Mr. Bankman-Fried has pleaded not guilty to the charges against him.

From his home confinement, Mr. Bankman-Fried has entertained visitors, including the author Michael Lewis, who is writing a book about him. He has also started mounting a defense, writing posts on Substack that detail his version of the events leading up to FTX’s collapse.

According to Friday’s filing, Mr. Bankman-Fried wrote to the general counsel of FTX U.S. on Jan. 15, saying he would “really love to reconnect and see if there’s a way for us to have a constructive relationship, use each other as resources when possible, or at least vet things with each other.”

Prosecutors said the witness “has firsthand knowledge of the defendant’s conduct during the charged conspiracies” and participated in communications on Signal and the messaging system Slack with a small group of insiders the month that FTX collapsed. Mr. Bankman-Fried has also contacted other current and former FTX employees, according to the filing.

The document does not identify the witness by name. The general counsel of FTX U.S. is Ryne Miller, according to his LinkedIn page.

For much of his tenure at FTX, Mr. Bankman-Fried relied on Signal, which gives people the option to automatically delete messages. According to prosecutors, he also directed employees of FTX and Alameda Research, a hedge fund he founded, to set their communications to automatically disappear after 30 days or less.

“The autodeletion of FTX and Alameda’s Slack and Signal communications has impeded the government’s investigation,” the filing said. “Potential witnesses have described relevant and incriminating conversations with the defendant that took place on Slack and Signal that have already been autodeleted.”

In the court filing, prosecutors said Mr. Bankman-Fried’s use of Signal could obstruct their efforts to determine whether he tried to contact more potential witnesses during his confinement.

“The proposed bail conditions in combination would more effectively prevent the defendant from obstructing justice,” the filing said.