TORONTO - Newly disclosed documents show Canada knew the United States secretly paid Pakistan $500,000 to capture Canadian citizen Abdullah Khadr in what his lawyers said Monday was another notorious example of Washington's outsourcing of torture.

The U.S., which is seeking to have Khadr extradited from Canada on charges he bought weapons for al Qaeda and plotted to kill American troops in Afghanistan, opted to use Pakistan to do its dirty work, the lawyers said.

"All the mistreatment that Mr. Khadr experienced in Pakistan is the U.S. government's responsibility,'' Nate Whitling, one of Khadr's lawyers, said in an interview from Edmonton.

"Now we know that they paid Pakistan to arrest him and they knew full well what would happen to him.''

At the request of the Americans, the Canadian government had sought to keep the information about the payment secret on the grounds that it would damage Canada's interests.

However, it was released publicly under court orders Monday following the lapse of an appeal period by the Crown.

"It is clear that Canadian officials were told that a bounty had been paid shortly after (Khadr's) capture and included that information, presumably considered reliable, in briefing their superiors,'' Federal Court Justice Richard Mosley said in his ruling.

"The sole justification that was provided to the court as to why publication of the information should be prohibited is that the (U.S.) does not want the information disclosed.''

Mosley wrote that Khadr should be allowed to raise the bounty at his extradition hearing, and said there would be no harm to Canada's national security or international relations in doing so.

Until the ruling, Khadr's lawyers had been barred from putting the information before the extradition judge.

Khadr was returned to Canada on Dec. 7, 2005, after spending a year in custody in Pakistan. He was arrested shortly after his return at the request of the Americans, who want him to stand trial in the U.S.

Whitling said the U.S. had tried to wash its hands of what happened to Khadr in Pakistan, even while relying on a self-incriminating statement he made in Pakistani custody to demand his extradition.

Khadr's lawyers have plans to argue

Human rights reports by the U.S. State Department point to a routine and systemic practice of arbitrarily detaining prisoners wanted for national security matters in isolation and torturing them to elicit confessions.

"So when they give Pakistan a wink and a nudge and say, `Pick this guy up for half-a-million bucks for national security reasons,' they know exactly what's going to happen to him,'' Whitling said.

Khadr's lawyers now plan to argue the statement he gave to the FBI in Pakistan, and a similar one later in Toronto, should be thrown out because they are the product of illegal detention and torture.

"The FBI goes in there, while he's under these deplorable conditions, and they interrogate him while there's a Pakistani intelligence official sitting in the room with him,'' Whitling said.

"He's obviously acutely vulnerable, and they get him to say what had already been elicited from him in earlier interrogations.''

Similarly, shortly after his return to Toronto, American intelligence officers simply got Khadr to reaffirm the written statement he'd provided in Pakistan.

The two statements essentially make up the extradition case against Khadr.

Unlike other bounties offered by the U.S. for specific individuals, this one was kept secret.

"Clearly the U.S. wished to maintain its ability to deny any involvement in what it knew would happen to Mr. Khadr,'' his lawyers said.

International human-rights groups such as Amnesty International and Human Rights Watch have condemned the American practice of paying bounties to countries with poor human rights records.

"(Pakistan's) security forces tortured and abused persons, often to elicit confessions,'' and "police and security forces held prisoners incommunicado and refused to provide information on their whereabouts, particularly in terrorism and national security cases,'' the U.S. State Department noted in 2004.

Khadr was expected in court Tuesday to set a further court date.