WASHINGTON (AP) — Disputing the conclusions of the CIA's independent watchdog, an independent board has asserted that CIA officers acted reasonably when they secretly searched Senate computers last year after learning that Senate aides had removed certain classified documents related to the torture investigation.

The board, which was led by former Democratic Senator Evan Bayh, found fault with some of the findings by the CIA's inspector general, who said in July that five CIA employees "improperly accessed" a Senate portion of a shared computer network.

The inspector general, David Buckley, resigned in December in what CIA officials insist is an unrelated development. CIA Director John Brennan apologized after the release of the inspector general report and convened the accountability board.

The Bayh-led board said the five CIA employees did not deserve to be punished.

"They acted reasonably under the complex and unprecedented circumstances involved in investigating a potential security breach in the highly classified shared computer network," the board said in a statement.

The CIA accessed five emails of Senate aides, but the board concluded the access was a mistake and did not reflect malfeasance or bad faith.

The board's report amounted to a remarkable turnabout in a long running dispute between Sen. Dianne Feinstein, D-Calif., the senior Democrat on the Senate Intelligence Committee, and CIA Director John Brennan about whether Feinstein's aides acted appropriately when they removed CIA documents they deemed highly incriminating — documents the CIA considered an internal review to which the Senate was not entitled.

The aides took the documents out of a Virginia facility run by the CIA which had been set up to allow Senate investigators to review classified material. The documents were redacted and taken to the Senate's secure facility in the Hart building near the Capitol. They were not used in the Senate report on CIA interrogations, which was harshly critical of the agency.

The documents, part of what is known as the "Panetta review," were compiled by CIA officers who were sifting through the millions of pages being turned over to the Senate as part of the Senate investigation into the CIA's brutal treatment of al-Qaida detainees after the 9-11 attacks.

Feinstein said last year that the Panetta review supported the Senate conclusions that CIA torture did not produce unique intelligence. And she said they were not consistent with the later CIA response, which disputed parts of the Senate report.

In a statement Wednesday, Feinstein said she continues to believe the "CIA's actions constituted a violation of the constitutional separation of powers" that led the CIA to make an erroneous referral for criminal charges against Senate staff to the Justice Department. No charges were ever filed.

"I'm thankful that Director Brennan has apologized for these actions, but I'm disappointed that no one at the CIA will be held accountable. The decision was made to search committee computers, and someone should be found responsible for those actions," Feinstein said.

A statement by the CIA simply restated the board's conclusions.

The documents in question were stored on a shared drive in the Virginia facility. The system contained extremely sensitive documents, including the true names of covert operatives.

According to the board's report, a message flashed on the screen that said, "Your use of this system may be monitored and you have no expectation of privacy."

Feinstein has said that Senate aides accessed the Panetta review using a Google search tool, and printed it out and removed it because of its importance.

After the CIA learned that Senate aides appeared to have taken the Panetta review without authorization, they began an investigation of the computer system to learn how the breach happened. There were no formal procedures governing how such a security check should be conducted, the board found.

The CIA conducted three separate searches of the computer system, one of which involved "inappropriate access to Senate work product," the board found. Five Senate emails were accessed.

But "because there was no formal agreement — or even clear common understanding — governing the procedures to be followed in investigating a potential security incident in these circumstances, no course of action was free of potential complication or conflict," the board said in justifying the CIA actions.