Attorney General Eric Holder signed off on the controversial warrant application that the Justice Department used to obtain the personal emails of a Fox News reporter.

The warrant, which was obtained after the Justice Department identified Fox News reporter James Rosen as a possible criminal co-conspirator for communicating with a source who allegedly supplied him with classified information, allowed investigators to obtain two days' worth of email correspondence from Rosen's personal Gmail account.

Holder said previously that he had recused himself from a separate leak investigation that involved reporters for the Associated Press, but did not do so in this case, and personally signed off on the warrant to obtain the reporter's emails, according to NBC. Holder recused himself in the previous case involving AP, because he said he himself had been questioned by investigators as a witness in that leak investigation.

In light of the controversy over this and another leak investigation that involved the work and personal phone records of reporters at the AP, President Barack Obama said in a recent speech that Holder has agreed to review the Justice Department's guidelines for handling investigations that involve journalists and journalist records.

"I am troubled by the possibility that leak investigations may chill the investigative journalism that holds government accountable," Obama said in the speech. "Journalists should not be at legal risk for doing their jobs."

In an effort to unmask a leaker who fed Rosen classified information about North Korea in 2009, FBI investigators tracked Rosen's movements in and out of the State Department building where he worked and took the unprecedented step of alleging to a court that Rosen had engaged in a criminal conspiracy simply for doing his job, so that investigators could obtain a warrant to read the reporter's personal emails.

The FBI took the aggressive steps against Rosen, Fox News's chief Washington, DC correspondent, over a story he published online in June 2009, according to the Washington Post.

Although investigators had already zeroed in on Stephen Jin-Woo Kim, an employee of Lawrence Livermore National Lab and a security adviser to the State Department, as the suspected leaker, and had examined Kim's computer and e-mails, federal investigators took the unprecedented step of telling a judge that Rosen was also a suspect in a criminal conspiracy to obtain the classified information simply based on the fact that Rosen had expressed interest to Kim in obtaining information from him.

According to the affidavit (.pdf), FBI Agent Reginald Reyes told the judge there was probable cause to believe that Rosen had violated the Espionage Act by serving “as an aider, abettor and/or co-conspirator” in the leak. The Espionage Act is the same law that former Army intelligence analyst Bradley Manning is accused of violating when he leaked information to the secret-spilling site WikiLeaks.

To support his assertion, Reyes quoted an email exchange between Kim and Rosen, in which Rosen told him that he was interested in "breaking news ahead of my competitors” and had a particular interest in “what intelligence is picking up.” He also told Kim, “I’d love to see some internal State Department analyses.”

The suggestion was that Rosen broke the law by soliciting information from Kim, something that all journalists do routinely with sources.

Nonetheless, the federal judge found there was probable cause to believe that Rosen was a co-conspirator and approved the warrant.

"Never in the history of the Espionage Act has the government accused a reporter of violating the law for urging a source to disclose information," Ben Wizner, director of the ACLU's Speech, Privacy and Technology Project said in a statement after the news broke last week. "This is a dangerous precedent that threatens to criminalize routine investigative journalism."

The revelations about the Rosen investigation come just a week after news reports revealed that federal investigators had obtained the phone records of journalists for the Associated Press for a leak investigation into a different story published last year about a CIA operation in Yemen that halted an al-Qaida plot to detonate a bomb on an airplane headed to the U.S.

In the AP investigation, the feds seized records for 20 separate phone lines, including the work and personal phone numbers of individual reporters, the general phone lines for AP bureaus in New York, Washington and Hartford, Connecticut, and a main number used by AP reporters in the House of Representatives. They did so with the approval of the Justice Department, which has insisted it followed its internal rules in signing off on the subpoena used to obtain the records.

In the AP case, the feds used an administrative subpoena to obtain the phone records, instead of a probable cause warrant, as they did in the Fox News case, which requires a judge's approval.

Although the Justice Department generally follows stricter rules that limit when it will seek a reporter's phone records and correspondence, these protections disappear if a journalist is suspected of breaking the law. But it remains to be seen whether a reporter communicating with sources can be prosecuted for seeking information.

A Justice Department spokeswoman defended the decision to have Holder review his own actions.

“This review is consistent with Attorney General Holder's long-standing belief that freedom of the press is essential to our democracy," she said in a statement to NBC. "At the same time, the attorney general believes that leaks of classified information damage our national security and must be investigated using appropriate law enforcement tools. We remain steadfast in our commitment to following all laws and regulations intended to safeguard national security as well as the First Amendment interests of the press in reporting the news and the public in receiving it."