(CNN) — Fox News was aware years ago that the Justice Department was targeting one of its reporters in a leak investigation, according to law enforcement sources.
One law enforcement source said the Justice Department notified a media organization almost three years ago of a subpoena for detailed telephone records, and a second told CNN that organization was Fox News.
The Justice Department was investigating Stephen Kim, a former State Department worker accused of the unauthorized disclosure of sensitive information to James Rosen, a Fox News reporter.
CNN and other media outlets have previously reported a separate Justice Department query into Rosen's e-mails. With the approval of Attorney General Eric Holder, Justice officials obtained a warrant from a federal judge to access Rosen's e-mails.
"In the investigation that led to the indictment of Stephen Kim, the government issued subpoenas for toll records for five phone numbers associated with the media," a law enforcement source told CNN. "Consistent with Department of Justice policies and procedures, the government provided notification of those subpoenas nearly three years ago by certified mail, facsimile and e-mail."
Fox had said it learned of the warrant for e-mails only recently, and newly released court documents show the government was trying to keep the investigation under seal.
The claims of the law enforcement sources -- that the network had been given notice of the investigation involving Rosen -- suggest that Fox could have known years ago that the Justice Department was going after its phone records.
The government's notice did not detail the extent of the investigation, in which the government labeled Rosen a possible co-conspirator. An FBI affidavit used to obtain the warrant for Rosen's e-mails described him as potentially being an "aider and abettor and/or co-conspirator" to the crime of disclosing government secrets.
Fox has not responded to repeated requests from CNN beginning Friday evening for comment.
The Justice Department has come under scrutiny this month as news broke of two government probes into reporters' records. Besides the Rosen case, the Associated Press announced the department had dug into the phone records of its reporters, including work, cell, and home lines.