In a new court filing obtained by The Canadian Press, Khadr says he knew the Americans could have held him indefinitely — even in the highly unlikely case he would have been acquitted.
"I was left with a hopeless choice," Khadr, 27, says in the affidavit sworn Friday.
"If I wanted the chance to eventually return to my home of Canada, I would have to be found guilty of crimes as determined by the U.S. government, which could then lead to me serving my sentence in Canada."
The affidavit, filed in Federal Court, comes as part of Khadr's $20-million lawsuit against the federal government for violation of his rights.
It also comes as Canadian prison authorities eased Khadr's security classification from maximum to medium.
Without the plea agreement he signed in October 2010, Khadr says he would have faced the possibility of life-long detention and "continued abuse and torture" at Guantanamo Bay.
The entire agreement, including the agreed stipulation of facts, was put together by the American government, he says.
The Toronto-born Khadr also makes it clear that — in contrast to the agreed facts in the plea deal — he has never believed Jews or Americans should be killed or deserve to die, and says he never willingly joined an al-Qaida terrorist cell.
"Any participation in al-Qaida-related activities was at the demand of the adults around me," his affidavit says — the first time Khadr has addressed such issues publicly.
He also says the American case against him was based in part on evidence supplied by Canadian intelligence officials, who interviewed him at the U.S. naval base after his transfer there from Afghanistan.
Documents also filed show Canadian intelligence officials, who were pursuing a case against Khadr's father and a possible terrorism case against him, knew the Americans would only grant access to the teen if they would share information with the U.S.
"U.S. State Department would permit Canadian authorities an opportunity to interview Omar Khadr should it be established that such interviews would further any investigation within their jurisdiction," according to one RCMP memo from September 2002.
Khadr's lawyers are trying to get those links included as part of the civil lawsuit against Ottawa, which has denied any wrongdoing.
The Americans detained Khadr as a terribly wounded 15-year-old following a four-hour firefight in Afghanistan in July 2002 in which a U.S. special forces soldier was killed.
Khadr says he has no memories of that battle or of the grenade that killed Sgt. Christopher Speer.
He also insists he had no plans to kill any soldiers, nor did he attack any of the U.S. forces who entered the compound after the battle was over.
Those denials, however, would have left him unable to enter the plea deal before a widely maligned military commission, which sentenced him to a further eight years behind bars.
Khadr was transferred to Canada in September 2012 to serve out the rest of his sentence, and is currently housed in the maximum security Edmonton Institution. However, his classification was changed Friday to medium security, his lawyer Dennis Edney said, and a transfer to another prison was expected within weeks.
"He should be released into the public," Edney said.
"The overwhelming evidence provided to the minister of public safety demonstrated he was not a security threat on his arrival back in Canada."
The federal government has repeatedly denounced Khadr as an unrepentant terrorist.
Khadr is also appealing his conviction in the U.S. on the basis that the offences to which he pleaded guilty — including murder in violation of the rule of law — have no validity in either international or American law.
His affidavit states that he never signed away his rights to appeal that conviction.
Khadr says his Guantanamo detention conditions deteriorated after he pleaded guilty, and he was interrogated for up to nine hours a day for nine or 10 days at a stretch.
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