Updated

Military psychologists were enlisted to help develop more aggressive interrogation methods, including snarling dogs, forced nudity and long periods of standing, against terrorism suspects, according to a Senate investigation.

Before they were approved by then-Defense Secretary Donald H. Rumsfeld, such harsh techniques had drawn warnings from military lawyers that they could be illegal, an investigation by the Senate Armed Services Committee has found. Officials familiar with the findings discussed them on condition of anonymity because the information has not been formally released.

Officials who worked on a program that trained U.S. troops to survive enemy interrogations were to testify Tuesday before the Senate committee, which was expected to release some details of its ongoing investigation.

The hearing is the committee's first look at the origins of the harsher methods used in Guantanamo Bay prison in Cuba and Abu Ghraib in Iraq and how policy decisions on interrogations were vetted across the Defense Department. Its review fits into a broader picture of the government's handling of detainees, which includes FBI and CIA interrogations in secret prisons.

Democrats contend that the Senate investigation will refute the Bush administration's argument that abusive conditions in some military prisons were only the result of a handful of personnel acting independently. Instead, they say, the conditions were the consequence of senior defense civilians eager to extract intelligence in the months following the Sept. 11 attacks.

The Pentagon's top civilian lawyer at the time, chief counsel William "Jim" Haynes, was expected to testify Tuesday. Also scheduled to be present were Richard Shiffrin, Haynes' former deputy on intelligence matters, as well as legal advisers at the time to the chairman of the Joint Chiefs of Staff and the Guantanamo Bay prison.

According to the Senate committee's findings, Haynes became interested in using harsher interrogation methods as early as July 2002 when he sent a memo inquiring about a military program that trained Army soldiers how to survive enemy interrogations and deny foes valuable intelligence. Jerald Ogrisseg, a former top military psychologist, was expected to testify Tuesday that the program was never intended to be a means of finding tougher ways to interrogate U.S. prisoners.

Shortly after requesting more information about harsh techniques, Haynes traveled in September 2002 to Guantanamo Bay with other administration lawyers, including then-White House Counsel Alberto Gonzales and Vice President Dick Cheney's chief counsel, David Addington.

A month later, the military commander in charge of Guantanamo Bay, Gen. Michael Dunlavey, asked his superiors at U.S. Southern Command for approval to employ harsher interrogations. According to officials familiar with the Senate investigation, the military services' lawyers told the Joint Staff that the techniques warranted further study, and the Air Force and Army specifically warned that the methods could be illegal. Their objections were ignored.