One can reasonably predict that this will become a huge scandal and that John Brennan's half-life as CIA chief is now very limited. McClatchy reports:

The CIA Inspector General’s Office has asked the Justice Department to investigate allegations of malfeasance at the spy agency in connection with a yet-to-be released Senate Intelligence Committee report into the CIA’s secret detention and interrogation program, McClatchy has learned.

The criminal referral may be related to what several knowledgeable people said was CIA monitoring of computers used by Senate aides to prepare the study. The monitoring may have violated an agreement between the committee and the agency.

The CIA spied on the Senate committee that oversees the CIA. I am not aware of a similar thing happening since the days of John Edgar Hoover at the FBI.

The Senate committee has been preparing a thick file on the CIA's use of torture after 9/11. The report, still secret, allegedly says that the torture program was inhumane and completely useless and that the CIA systematically lied about its usefulness. The CIA protested and claimed that the committee report was wrong. But an internal study done by the CIA itself confirmed the still secret Senate committee report. To find out how the Senate committee got it hands on the internal CIA study the CIA bugged the computer networks the committee was using for its investigation. That last step is likely to now break some CIA necks.

At the center of this scandal is CIA chief and drone killing promoter John Brennan who was in a leading CIA position when the torture happened. I find it likely that he is personally responsible for the coverup attempt just as he personally was responsible for the crime itself. The New York Times has some additional details:

The agency’s inspector general began the inquiry partly as a response to complaints from members of Congress that C.I.A. employees were improperly monitoring the work of staff members of the Senate Intelligence Committee, according to government officials with knowledge of the investigation.

The committee has spent several years working on a voluminous report about the detention and interrogation program, and according to one official interviewed in recent days, C.I.A. officers went as far as gaining access to computer networks used by the committee to carry out its investigation.
…
[L]ast June, John O. Brennan, the C.I.A. director, responded to the Senate report with a 122-page rebuttal challenging specific facts in the report as well as the investigation’s overarching conclusion — that the agency’s interrogation methods yielded little valuable intelligence.

Then, in December, Mr. Udall revealed that the Intelligence Committee had become aware of an internal C.I.A. study that he said was “consistent with the Intelligence Committee’s report” and “conflicts with the official C.I.A. response to the committee’s report.”

It appears that Mr. Udall’s revelation is what set off the current fight, with C.I.A. officials accusing the Intelligence Committee of learning about the internal review by gaining unauthorized access to agency databases.

What chutzpah. The CIA claims that the Senate Select Committee on Intelligence overseeing the intelligence community should not have access to intelligence reports that set the agencies in bad light.

The NYT also reveals that contracters(!) review all papers before the government employees of the Senate committee staff are allowed to see them.

Now, the intelligence committee is well know for usually being very protective of the spies, but I find it likely that it will react very harsh to being spied on itself.

Any pretense of a functioning democracy becomes incredible when the executive subverts the legislative arm overseeing it. To keep up the pretense will now necessitate a big purge at the CIA.