The Justice Department is conducting an internal inquiry into the role its lawyers played in approving the legal opinions and memos on interrogation techniques, including waterboarding, Attorney General Michael Mukasey confirmed Friday.
Sens. Richard Durbin, D-Ill., and Sheldon Whitehouse, D-R.I., released a letter Friday acknowledging an investigation being conducted by the Justice Department's Office of Professional Responsibility (OPR), an internal watchdog that monitors decisions and actions of the department's lawyers.
The Feb. 18 letter from H. Marshall Jarrett, the chief of OPR, notes the investigation concerns the "circumstances surrounding the drafting of the August 1, 2002 memorandum from the Department's Office of Legal Counsel (OLC) to Alberto Gonzales, then the counsel to the President." Gonzales became Attorney General in 2005, and resigned last August.
The controversial memo, issued under Jay Bybee, then OLC head, but written in large part by John Yoo, one of his assistants, concluded that a definition of torture "covers only extreme acts," opening the door to legal justification for certain harsh interrogation tactics.
When asked by ABC News about the investigation and the formation of the memo at a press conference at the Justice Department Friday, Mukasey stated, "I have no reason to believe that politics was involved in that or any other analysis."
"There is, as you pointed out, a letter reflecting that there is an OPR inquiry at the request of two senators into the drafting of those letters and whether people adhered to professional standards in doing that," he continued. "But that's what there is, an inquiry, into that aspect."
Sources inside the Justice Department say that administration officials and top department officials, including former Attorney General John Ashcroft, were uncomfortable with some of Yoo's legal arguments.
Former aides to Ashcroft say the then-attorney general privately dubbed Yoo "Dr. Yes" for being so closely aligned with lawyers at the White House.
Yoo, who left the Justice Department in 2003 and is now a law professor at the University of California-Berkeley, defended his legal stance, telling the Associated Press last year that the department shouldn't go "about, willy-nilly, changing its opinions about what's legal or not."
He added that intelligence agents should be able to focus on "fighting the enemy," not "worrying about whether they will be prosecuted by their own government" if different administrations switch up the rules.
The OPR letter to the senators notes, "We are examining whether the legal advice contained in those memoranda was consistent with the professional standards that apply to Department of Justice attorneys."
In a statement Sen. Whitehouse said, "This abject failure of scholarship suggests that the answer was preordained and the Department was driven by politics and obedience, not law and independence. I welcome OPR's report in our continuing effort to reclaim DOJ from the 'loyal Bushies' who have besmirched a great institution."
While the probe is set to look at the 2002 memos and legal guidance that laid it out, a December 2004 memo rescinded the guidance. That memo noted that while they disagree with the 2002 memos, nothing in it was determined to be illegal: "We have reviewed this Office's prior opinions addressing issues involving treatment of detainees and do not believe that any of their conclusions would be different under the standards set forth in this memorandum."
The investigation is separate from a criminal inquiry being overseen on the destruction of CIA interrogation tapes, which is being run by U.S. Attorney John Durham from the District of Connecticut, as the U.S. Attorney for the Eastern District of Virginia has recused his office from the investigation.
ABC News' Theresa Cook contributed to this report.