So began an operation the CIA calls an "extraordinary rendition," the forcible and highly secret transfer of terrorism suspects to their home countries or other nations where they can be interrogated with fewer legal protections.

The practice has generated increasing criticism from civil liberties groups; in Sweden a parliamentary investigator who conducted a 10-month probe into the case recently concluded that the CIA operatives violated Swedish law by subjecting the prisoners to "degrading and inhuman treatment" and by exercising police powers on Swedish soil.

"Should Swedish officers have taken those measures, I would have prosecuted them without hesitation for the misuse of public power and probably would have asked for a prison sentence," the investigator, Mats Melin, said in an interview. He said he could not charge the CIA operatives because he was authorized to investigate only Swedish government officials, but he did not rule out the possibility that other Swedish prosecutors could do so.

The basic facts of the Stockholm rendition were reported last year; this article is based on newly released documents from the parliamentary probe that provide elaborate details about an operation that normally unfolds entirely out of public view and about the government deliberations that preceded it.

Swedish security police said they were taken aback by the swiftness and precision of the CIA agents that night. Investigators concluded that the Swedes essentially stood aside and let the Americans take control of the operation, moving silently and communicating with hand signals, the documents show.

"I can say that we were surprised when a crew stepped out of the plane that seemed to be very professional, that had obviously done this before," Arne Andersson, an assistant director for the Swedish national security police, told government investigators.

At 9:47 p.m., less than an hour after its arrival at Bromma Airport, the jet took off on a five-hour flight to Cairo, where the prisoners, Ahmed Agiza and Muhammad Zery, were handed over to Egyptian security officials.

The CIA has not acknowledged playing any part in the expulsion of the two men. An agency spokesman in Washington declined to comment for this article, and U.S. Embassy officials in Stockholm also declined to answer questions.

CIA officials have testified that they have used rendition for years after tracking down suspected terrorists around the world. They say the U.S. government receives assurances of humane treatment from the countries where the suspects are taken. Human rights groups say that such pledges, from governments with long histories of torture, are worthless.

The two Egyptians later told lawyers, relatives and Swedish diplomats that they were subjected to electric shocks and other forms of torture soon after their forced return to their country.

Agiza, a physician, was convicted in an Egyptian military court and sentenced to 15 years in prison after a trial that lasted six hours. He was charged with being a leader of Egyptian Islamic Jihad, a radical group that the U.S. government has listed as a terrorist organization. He and his lawyers have acknowledged that he once worked with Ayman Zawahiri, a fellow Egyptian and the ideological leader of al Qaeda, but say that he cut ties with the group many years ago.

Zery was released from prison in October 2003. Egyptian officials notified the Swedish government last year that he was no longer under suspicion. His lawyer said he remained under surveillance.

The Swedish government kept the CIA's role in the case a secret for more than three years. Then, in 2004, following unofficial reports of the rendition, it released documents showing that a U.S.-registered plane had been used to transport the Egyptians to Cairo but said the details were classified. It wasn't until March, when the parliamentary investigator released his findings, that the CIA's direct involvement was publicly confirmed.

The revelations created a stir in Sweden, which has long been outspoken in its support of international human rights. A parliamentary committee is scheduled to open hearings on government officials' handling of the expulsion.

Although the parliamentary investigator concluded that the Swedish security police deserved "extremely grave criticism" for losing control of the operation and for being "remarkably submissive to the American officials," no Swedish officials have been charged or disciplined.

"It's quite clear that laws were broken. It is against Swedish law and against international law," said Anna Wigenmark, a lawyer for the Swedish Helsinki Committee for Human Rights, which has worked on behalf of the Egyptian suspects. She and other human rights advocates have charged that the treatment of Agiza and Zery also violated the European Convention on Human Rights.

"It's unacceptable that something like this could happen on Swedish soil and yet nothing has been done about it," Wigenmark said.

Before their expulsion, the two men had lived in Sweden for extended periods and had applied for political asylum.

The Swedish government has revealed little about why it suddenly decided to expel them, three months after the Sept. 11, 2001, attacks in the United States. It has said only that the decision was made on the basis of secret intelligence information, some of it from foreign services, indicating that the men posed a security threat. Swedish officials have refused to disclose any of the evidence or reveal where the information came from.

Fresh details of the transfer are contained in more than 100 pages of interview transcripts with Swedish police officers who witnessed the events at the Stockholm airport and police commanders who oversaw the case, as well as in other documents from the national security police. The records describe a hectic and haphazardly planned effort to deport the men.

Swedish security police wanted to arrest the men and put them on a flight to Cairo immediately to avoid giving their lawyers a chance to file an emergency appeal in court.

Swedish government ministers hastily scheduled a meeting for Dec. 18, 2001, to formally approve the expulsion. But the security police were unable to charter a flight to take the Egyptians to Cairo until the next morning. Police officials, worried about an overnight delay, turned to the CIA for help, according to the documents.

CIA officials told the Swedes they had a private jet with special security clearances that could fly nonstop to Cairo on a moment's notice. Andersson, the Swedish police commander in charge of the case, characterized the offer as a "friendly favor from the CIA which allowed us to have a plane that had direct access throughout Europe and could take care of the operation very rapidly."

About 2:30 p.m. on Dec. 18, the CIA plane left Cairo for Stockholm. About a half-hour later, the Swedish government ministers voted to expel Agiza and Zery.

By 5 p.m., Swedish police had arrested both men and were waiting for the plane to arrive. Already, however, problems had begun to surface.

Two unnamed officials from the U.S. Embassy informed Swedish officers that there would be no room on the jet for them on the trip back to Cairo. The Swedes complained and were ultimately given two seats on the plane, but raw feelings persisted.

"I felt that they were backing into our territory," an unidentified female Swedish security officer told investigators, according to a transcript of her interview.

More conflicts arose after the plane landed. One Swedish officer walked up the steps of the aircraft to greet the crew and was surprised to see that the agents -- a half-dozen or so Americans and two Egyptians -- were wearing hoods with semi-opaque fabric around the face, even though the small airport was essentially deserted.

"I told them that you don't need to wear hoods because there is no one here," the officer recalled in his statement to investigators. The foreign agents ignored him.

The Swedish police said they were also perplexed by a demand from U.S. agents that they be allowed to strip-search the prisoners, even though the two men had already been searched and were in handcuffs. The Swedes relented after the captain of the plane said he would refuse to depart unless the Americans were allowed to do things their way, the documents show.

The prisoners were taken into the airport police station, one by one, to be searched.

One agent quickly slit their clothes with a pair of scissors and examined each piece of cloth before placing it in a plastic bag. Another agent checked the suspects' hair, mouths and lips, while a third agent took photographs from behind, according to Swedish officers who witnessed the searches.

As the prisoners stood there, naked and motionless, they were zipped into gray tracksuits and their heads were covered with hoods that, in the words of one Swedish officer, "covered everything, like a big cone."

Swedish police later marveled that the whole search procedure took less than 10 minutes. "It surprised me," one officer told investigators. "How the hell did they dress him so fast?"

Paul Forell, a Swedish airport police officer who was on duty that night, added: "Everything was very smooth, professional. I mean, I thought, they have done this before."

Zery later complained to his lawyers that the CIA agents tranquilized him by inserting suppositories in his anus during the search and that the two prisoners were forced to wear diapers. Swedish police officers said they couldn't recall if the Egyptians had been forcibly medicated.

Investigators did find a report written by one of the Swedish officers that said Agiza and Zery were both "probably given a tranquilizer before takeoff."

While investigators said they could not prove that the prisoners had been forcibly medicated, such a tactic would have violated Swedish law.

In a January letter to parliamentary investigators, the new director of the security police, Klas Bergenstrand, said the decision to rely on the CIA was a mistake.

"In my judgment, it is clear that some of the measures adopted after the two Egyptians had arrived at Bromma Airport were excessive in relation to the actual risks that existed," Bergenstrand wrote. "For my part, I would find it alien to use a foreign aircraft with foreign security staff."

© 2005 The Washington Post Company