Gen. Bantz Craddock, commander of the U.S. Southern Command, testifies about the investigation of alleged detainee abuse at Guantanamo Bay.

Interrogators at the U.S. detention facility at Guantanamo Bay, Cuba, forced a stubborn detainee to wear women's underwear on his head, confronted him with snarling military working dogs and attached a leash to his chains, according to a newly released military investigation that shows the tactics were employed there months before military police used them on detainees at the Abu Ghraib prison in Iraq.

The techniques, approved by Defense Secretary Donald H. Rumsfeld for use in interrogating Mohamed Qahtani -- the alleged "20th hijacker" in the Sept. 11, 2001, terrorist attacks -- were used at Guantanamo Bay in late 2002 as part of a special interrogation plan aimed at breaking down the silent detainee.

Military investigators who briefed the Senate Armed Services Committee yesterday on the three-month probe, called the tactics "creative" and "aggressive" but said they did not cross the line into torture.

The report's findings are the strongest indication yet that the abusive practices seen in photographs at Abu Ghraib were not the invention of a small group of thrill-seeking military police officers. The report shows that they were used on Qahtani several months before the United States invaded Iraq.

The investigation also supports the idea that soldiers believed that placing hoods on detainees, forcing them to appear nude in front of women and sexually humiliating them were approved interrogation techniques for use on detainees.

A central figure in the investigation, Maj. Gen. Geoffrey Miller, who commanded the detention facility at Guantanamo Bay and later helped set up U.S. operations at Abu Ghraib, was accused of failing to properly supervise Qahtani's interrogation plan and was recommended for reprimand by investigators. Miller would have been the highest-ranking officer to face discipline for detainee abuses so far, but Gen. Bantz Craddock, head of the U.S. Southern Command, declined to follow the recommendation.

Miller traveled to Iraq in September 2003 to assist in Abu Ghraib's startup, and he later sent in "Tiger Teams" of Guantanamo Bay interrogators and analysts as advisers and trainers. Within weeks of his departure from Abu Ghraib, military working dogs were being used in interrogations, and naked detainees were humiliated and abused by military police soldiers working the night shift.

Miller declined to respond to questions posed through a Defense Department liaison. Bryan Whitman, a Pentagon spokesman, said it is not appropriate to link the interrogation of Qahtani -- an important al Qaeda operative captured shortly after the terrorist attacks -- and events at Abu Ghraib. Whitman said interrogation tactics in the Army's field manual are the same worldwide but MPs at Abu Ghraib were not authorized to apply them, regardless of how they learned about them.

Some of the Abu Ghraib soldiers have said they were following the directionsof military intelligence officials to soften up detainees for interrogation, in part by depriving them of sleep. Pvt. Charles A. Graner Jr., characterized as the ringleader of the MP group, was found guilty of abusing detainees and is serving 10 years in prison. Others have pleaded guilty and received lesser sentences.

The photos that caused alarm around the world included some showing the MPs sexually humiliating the detainees.

While Rumsfeld approved a list of 16 harsh techniques for use at Guantanamo on Dec. 2, 2002, most of the techniques were general and allowed for interpretation by interrogators. Many of the techniques involving humiliation were part of a standard "futility" or "ego down" approach.

"Reasonable people always suspected these techniques weren't invented in the backwoods of West Virginia," said Tom Malinowski, the Washington director of Human Rights Watch. "It's never been more clear than in this investigation."

Also yesterday, a federal district judge in Washington issued a ruling in which he declined to stop the interrogation of a young Canadian detainee at Guantanamo Bay who has alleged that he was tortured. The detainee said in court filings that he was "short-shackled" to the floor, threatened with sexual abuse and physically mistreated.

The 18-year-old detainee, identified as "O.K.," was arrested after a gunfight in Afghanistan in July 2002, when he was 15. He had asked the court for a preliminary injunction to stop what he called abusive interrogation tactics.

The investigation at Guantanamo Bay looked into 26 allegations by FBI personnel that military interrogators had mistreated detainees. It found that almost all the tactics were "authorized" interrogation methods and by definition were not abusive.

Investigators found only three instances of substantiated abuse, including short-shackling detainees to the floor in awkward positions, the use of duct tape to keep a detainee quiet, and a threat by military interrogators to kill a detainee and his family.

In the case of Qahtani, who endured weeks of sleep deprivation and many of the harshest techniques, Lt. Gen. Mark Schmidt and Brig. Gen. John Furlow found that the cumulative effect of those tactics "resulted in degrading and abusive treatment" but stopped short of torture. Military commanders have said the techniques prompted Qahtani to talk.

The military achieved "solid intelligence gains," by interrogating Qahtani, Craddock said yesterday, and other military officials have said he revealed details on how the terrorist network operates.

The Schmidt-Furlow investigation is the last of about a dozen major Pentagon probes into abuse over the past 15 months.

The abuses at Abu Ghraib included military police taking photos of themselves mimicking the tactics used at Guantanamo Bay. Several photographs taken in late 2003 at the prison outside Baghdad show detainees wearing women's underwear on their heads, detainees shackled to their cell doors or beds in awkward positions, and naked detainees standing before female soldiers. Perhaps the most famous image is of Pfc. Lynndie England holding a leash attached to a detainee's neck.

Qahtani, according to the investigative report, was once attached to a leash and made to walk around the room and "perform a series of dog tricks." The report also notes the use of "gender coercion," in which women straddle a detainee or get too close to them, violating prohibitions for devout Muslim men on contact with women. Interrogators also threatened to tell other detainees that an individual is gay, according to the report. Detainees at Abu Ghraib were posed in mock homosexual positions and photographed.

"There are some striking similarities between the actions at Guantanamo and what occurred at Abu Ghraib," said Capt. Jonathan Crisp, England's military defense attorney. "I feel that warrants further investigation."

Committee Democrats appeared upset that Miller was not held accountable for abuses at Guantanamo Bay, and criticized the investigation for failing to examine the legality of administration and military policy on interrogations. Sen. Jack Reed (D-R.I.) said no senior leader has taken responsibility for detention problems.

Some Republicans, however, said the alleged abuses occurred in just a small fraction of cases. They noted that there have been 24,000 interrogations at Guantanamo Bay and highlighted recent improvements at the facility. Sen. Pat Roberts (R-Kan.) called the Guantanamo abuse relatively "minor incidents" that should not be a matter of national interest.