The two haggard men stared at each other for long seconds, Arar recalled in an interview here this week. Then they realized: They were both Canadian.

Arar, 34, a computer engineer who was born in Lebanon, says he was spirited by U.S. authorities to Syria in 2002 and underwent repeated torture while held there for nearly a year. Now, a judicial commission here is seeking to determine how he and three other Arab Canadian citizens wound up being interrogated in the same Syrian prison after coming to the attention of Canadian or U.S. authorities.

Although much of the inquiry has been conducted behind closed doors, a recent series of public hearings has embarrassed the Canadian government by exposing details of Arar's "extraordinary rendition" -- the phrase used by the CIA to describe the U.S. practice of secretly sending terror suspects to countries where torture is routine. The hearings have also revealed a greater Canadian role in the practice than previously acknowledged.

The case has added to the growing discomfort of U.S. allies over such tactics in the war on terrorism. Critics in Sweden and Italy as well as Canada have called their governments to task for cooperating in U.S. renditions, which they say violate human rights.

In Canada, the Arar inquiry has sullied the country's self-image as a principled defender of human rights and may result in a call for tighter limits on intelligence-sharing between Canada and the United States, according to analysts and people involved in the process.

"Most Canadians are sensitive to civil liberties," said Paul J.J. Cavalluzzo, the lead counsel for the inquiry commission, which is headed by the associate chief justice of Ontario province. "They understand it's a bad world out there. But it doesn't mean we should turn our country into a police state. If we do that, we have lost."

The United States has refused to cooperate in the hearings, declining to send witnesses or documents.

The inquiry began after Arar was released without charges by Syria and returned to his family in Ottawa in October 2003. Since then, a series of hearings has disclosed that Canadian intelligence agents met with Arar's Syrian jailers and exchanged information with Syrian officials about Arar. They also suggested that Canadian diplomats were more anxious to see their own countryman interrogated than released.

The government's embarrassment was capped this month by the appearance before the commission of Canada's former ambassador to Damascus, Franco Pillarella, who said he did not know Syria used torture in its jails, despite widespread documentation of such practices by international human rights groups. His icy testimony brought an outpouring of mockery in the press.

"The more officials testify, the worse the picture gets," complained an editorial in the Ottawa Citizen newspaper.

Arar and other observers, however, have expressed more concern about what is not being divulged. Most testimony has been taken in 65 sessions that were closed to the public, including Arar. Many documents submitted in evidence are full of blacked-out redactions. And this week, the scheduled testimony of a key Royal Canadian Mounted Police supervisor was postponed while lawyers wrangled over the how much he should say in public.

"With eight months of [private] hearings, and less than two months of public hearings, it's hard for me to tell what's been discussed," complained Arar, who has sat through most of the open sessions.

Reserved and somber, Arar has been unemployed since he lost his engineering job while in prison. His wife, Monia Mazigh, campaigned to win his release, and she now works to support the family. They live in a tidy apartment outside Ottawa with their son, 3, and daughter, 8.

Arar, who came to Canada at age 17, holds both Syrian and Canadian citizenship. He insists he has never been involved in radical politics. According to information disclosed in the inquiry, the anti-terrorism unit of the Royal Canadian Mounted Police opened a file on him after observing him with two other men who were already being watched.

Arar has since claimed that both those men, Syrian-born Abdullah Almalki and Kuwaiti-born Ahmad Abou El-Maati, were merely casual acquaintances of his in the small Muslim communities of Ottawa and Montreal.

On Sep. 26, 2002, Arar said, he was pulled aside by police at New York's John F. Kennedy International Airport as he was changing planes on his way back to Canada after visiting his wife's family in Tunisia. After 12 days of questioning, he said, he was shackled, flown to Washington and on to Jordan, and then driven to an intelligence prison in Syria.

There, Arar has said, he was confined in a dark cell the size of a coffin for 10 months, beaten with electrical cords and reduced to wretched, weepy state in which he signed false confessions about training in Afghanistan, a place he later said he has never been.

"I was living a normal life. In the middle of that, I was taken and shipped to Syria, where it changed me 180 degrees," he said. "I lost a year of my life -- actually, a lot more. I'm still living in a different, psychological prison."

The State Department, which acknowledges Arar was sent to Syria, has said he was picked up by U.S. officials "based on information received from Canada." However, it has also said that Canada's "approval or consent was not sought" in the decision to ship him to a foreign prison. Arar said he wonders whether Washington is trying to provide cover for its ally.

"I want to know if I was sent to Syria on behalf of Canadian security agencies," he said in an interview at his apartment. "When the Americans asked, did they nod?"

Others, including several public interest groups here, have asked whether Canada has facilitated the interrogation of other citizens overseas, including Almalki, the bruised and hollow-eyed man whom Arar met in prison. Like Arar, Almalki was released by Syria without charge last year and returned to Canada after nearly two years in prison.

El-Maati and a third Canadian returned from Syria, Iraqi-born Muayyed Nureddin, have made similar charges through family members, lawyers or human rights groups. All three men have declined to be interviewed by journalists, reportedly for fear that publicity could bring harm to relatives still overseas, but information on their cases has been presented to the judicial inquiry.

Unlike Arar, none of the others claimed they had any contact with U.S. authorities; they were allegedly detained while traveling in Syria. However, all three were the focus of investigations by Canadian intelligence agents, and each has claimed that Syrian interrogators asked questions that could have come only from Canadian investigators, according to Alex Neve, the head of Amnesty International's office in Canada.

"It certainly points to there having been some kind of information exchange between security forces in Canada and Syria," said Neve, one of 18 representatives of public interest organizations that have been included in the public portions of the Arar hearings.

Asked for comment, a spokeswoman for the Royal Canadian Mounted Police said the agency was limited in what it could say "because the commission [inquiry] is still going on."

The head of the commission, Justice Dennis R. O'Connor, has said he wants to complete separate public and classified reports by the end of the year.

Wesley Wark, a security specialist at the University of Toronto, said the country's intelligence agencies are "fearful they will be hung out to dry for doing what they were told to do" by the government after Sept. 11, 2001.

He said they were also worried that the inquiry would lead to restrictions on Canada's intelligence operations and that the government might even "try to build some human rights context into intelligence sharing. They can't see any benefit in this inquiry," he said.