In a court filing made public Friday in Manhattan federal court, a prosecutor said Anthony Murgio, who was charged for operating an unlicensed bitcoin exchange service, was in discussions "regarding a possible disposition of this case."
The filing used language that is typically indicative of plea talks, though cases sometimes also can be resolved with deferred prosecution agreements or with charges being dropped.
The filing by Eun Young Choi, a prosecutor under Manhattan US Attorney Preet Bharara, came two weeks after authorities disclosed similar discussions were underway with Murgio's co-defendant, Yuri Lebedev.
In light of the discussions, US Magistrate Judge Frank Mass entered an order extending the deadline for when a grand jury would need to indict Murgio to October 9.
A spokeswoman for Bharara declined comment on Monday. Gregory Kehoe, Murgio's lawyer, did not immediately to requests for comment.
Any plea secured in the case could mark a breakthrough for authorities investigating the hacking of JPMorgan, which compromised information in 83 million household and small business accounts.
US and Israeli authorities arrested four people in Israel and Florida in July in connection with two separate fraud schemes.
While the cases appeared distinct and made no mention of the JPMorgan hacking, a person familiar with the matter has said both actions stemmed from the Federal Bureau of Investigation's investigation of the cyber-attack.
In one indictment, US authorities accused Murgio and Lebedev, both of Florida, of operating an underground bitcoin exchange, called Coin.mx, that was used to facilitate criminal activity including cyber-attacks.
In another indictment, authorities accused three men of engaging in a stock manipulation scheme involving US penny stocks.
In that case, Gery Shalon and Ziv Orenstein, both Israeli nationals, were arrested, and the US government has sought their extradition.
Joshua Samuel Aaron, a US citizen who resides in Moscow and Tel Aviv, remains at large, authorities have said.
The case is US v. Murgio, US District Court, Southern District of New York, No. 15-mj-02508.
© Thomson Reuters 2015