Anthony Murgio, a Florida man who was charged last month by federal prosecutors in Manhattan with running an illegal bitcoin money exchange firm and is thought to have information about last summer’s hacking attack against JPMorgan Chase, seemed to be taking the unfolding criminal case against him in stride during a court appearance on Monday morning.

Mr. Murgio, 31, made small talk with the two federal agents in the hallway of the federal court in Lower Manhattan, while waiting to appear on those charges before the United States magistrate judge, James C. Francis IV. At one point, he even rushed to see if a woman who had fallen in the hallway was hurt and needed help getting up.

But when he appeared in court, Mr. Murgio said nothing, letting his lawyer, Gregory W. Kehoe of the big law firm Greenberg Traurig, do the talking. The hearing was brief and the judge allowed Mr. Murgio, who has run a number of less-than-successful businesses since graduating from Florida State University, to remain free on $100,000 bail.

Mr. Murgio posted the bail a week ago after his arrest on July 21 in Tampa after spending a few nights in the Pinellas County jail while he and his family secured the money.