A foreign hacker compromised files relating to the FBI¡¯s investigation of the late sex offender Jeffrey Epstein during a break-in at the bureau¡¯s New York Field Office three years ago, according to a source familiar with the matter and recently published Justice Department documents.

The details of who accessed a server at the FBI¡¯s New York Field Office, including the allegation that a foreign hacker was involved, are being reported here for the first time.

In a statement, the FBI said what it described as a ¡°cyber incident¡± was ¡°an isolated one.¡±