The names of Mr. Murgio and Mr. Aaron surfaced last fall in the early days of a Federal Bureau of Investigation inquiry into the JPMorgan Chase breach that led to the theft of email addresses and contact information for more than 83 million customer accounts, said people briefed on the matter who spoke on the condition of anonymity. Federal authorities have not commented on what led them to identify Mr. Murgio and Mr. Aaron early in the inquiry and no one has been charged with the attack against JPMorgan, the nation's largest bank. So far, Mr. Murgio, Mr. Aaron, Mr. Lebedev and two other men also charged by prosecutors are accused of committing crimes that on the surface appear to be unrelated. Mr. Murgio and Mr. Lebedev are charged with running an illegal Bitcoin money transfer operation called Coin.mx, which processed transactions for web criminals who plant malicious software, called ransomware, to seize control of computers.