​The Federal Bureau of Investigation has reportedly taken the reins of a probe established to uncover the facts of an escalating scandal between the Central Intelligence Agency and the United States Senate surrounding classified documents.

Government sources told journalists working for McClatchy this week that the FBI is investigating allegations that sensitive materials were removed from a Northern Virginia CIA facility, reportedly by Senate Intelligence Committee staffers at work on the panel’s four-year-long study into advanced interrogation techniques used by the agency overseas against suspected terrorists.

According to a report first filed by the Associated Press on Thursday, Senate Intelligence Committee Chairwoman Dianne Feinstein told reporters that the CIA general counsel’s office was “investigating how her committee investigated allegations of CIA abuse in a Bush-era detention and interrogation program.”

“Two officials familiar with the investigation [say] the senator confirmed the CIA is looking into allegations of wrongdoing, including whether its own officers improperly monitored Senate investigators and possibly accessed their computers,” AP reported.

Shortly after that dispatch was published, McClatchy’s sources said on condition of anonymity that the investigation has since been referred by the CIA general counsel’s office to the Department of Justice, which oversees the FBI.

Now according to McClatchy, the Justice Dept. has been asked twice to investigate separate allegations pertaining to the report, which the committee intended on releasing nearly 15 months ago.

The CIA has yet to authorize the release of the classified 6,300-page study estimated to have cost the US government $40 million, however, and now its publishing date may be delayed further as the Justice Dept. considers no fewer than two requests related to the report: one involving the alleged removal of secret documents from that CIA facility, and another to determine if committee staffers were illegally spied on by the CIA.

It is not clear when the referrals were made, when the FBI became involved, or whether the FBI investigation also includes the computer monitoring, McClatchy’s journalists reported. The DOJ, FBI, CIA, and Senate Intelligence Committee have all deferred requests for comment.

Nevertheless, McClatchy’s Jonathan Landay, Ali Watkins, and Marisa Taylor wrote that the FBI’s newly unveiled involvement in the Senate report “takes to a new level an extraordinary behind-the-scenes battle over the report that has plunged relations between the agency and its congressional overseers to their iciest in decades.”

If allegations waged by the intelligence committee are correct, then the Senate members or staffers who viewed secret documents at the Langley, Virginia facility were being unknowingly monitored by the CIA. The agency may only be able to prove that documents were taken from the secret site by acknowledging the surveillance efforts they undertook.

The very document that Senate staffers have been accused of pilfering from the protected facility was described by McClatchy as a top-secret internal CIA review authorized by then-Director Leon Panetta “that broadly corroborated their report’s findings.”

But John Brennan, the agency’s current director, remains unready for the final report to be released, at least as of January 29.

“I said there were things in that report that I disagreed with, there were things in that report that I agreed with. And I look B to working with the committee on the next steps in that report,” Brennan said then.

A supposedly stolen internal review may show that the CIA is ready to release the report, which is now the subject of the agency’s contention.

“[I]t appears that the CIA is attempting, weakly, to spin this as being the Senate staffers' fault, arguing that the real breach was the fact that the Senate staffers somehow broke the rules in obtaining that internal review,” TechDirt journalist Mike Masnick wrote on Friday.

According to McClatchy’s source, “The staff printed out the draft, walked the document out of the CIA facility and took it to Capitol Hill” — which the CIA considered to be the unauthorized removal of classified material and a violation of a user agreement.

“I am deeply dismayed that some members of the Senate have decided to make spurious allegations about CIA actions that are wholly unsupported by the facts,” CIA Director John Brennan said in a statement this week.

“I am very confident that the appropriate authorities reviewing this matter will determine where wrongdoing, if any, occurred in either the executive branch or legislative branch,” he continued, suggesting that he believes an investigation may very well find the committee staffers at fault.

Sen. Feinstein, the chairperson of the Senate Select Committee on Intelligence, told The New York Times that “Our oversight role will prevail.”