U.S. NAVAL BASE GUANTANAMO, Cuba -- The likelihood the United States subjected Omar Khadr to harsh interrogations some would call torture increased Thursday after it emerged one of his early interrogators had been court-martialled for abusing prisoners and had also been involved in an interrogation of a detainee who died.

Legal arguments before the U.S. war crimes commission in Guantanamo Bay indicated Sgt. Joshua Claus of military intelligence participated in many, maybe all, of the interrogations of the Canadian terror suspect after U.S. forces delivered him to the Bagram detention centre in Afghanistan in July 2002.

A U.S. army investigation into the deaths of two other Bagram detainees in late 2002 describes a litany of coercive techniques he allegedly used to interrogate one of the men.

The disclosure came on a day Mr. Khadr's defence lawyers also highlighted a critical change made to a senior commander's report of the firefight in which the Canadian is accused of killing a U.S. soldier in a grenade attack.

Speaking afterward with reporters, Mr. Khadr's military lawyer, navy Lt.-Cmdr. Bill Kuebler, charged the change helped what he called the U.S. government's "manufactured" theory about what happened the day of Mr. Khadr's capture.

The author of the combat report, identified as Lt.-Col. "W," initially wrote July 28, 2002, that another U.S. operative subsequently killed the fighter who "engaged" the deceased U.S. soldier, Lt.-Cmdr. Kuebler told the commission.

About two months later, a new report -- bearing the same July date -- emerged saying the fighter had not been killed.

This is significant, because a separate confidential combat report inadvertently released to journalists last month revealed for the first time that a second fighter had been present alongside Khadr at the time the grenade was thrown. That fighter, who was killed, could be the person Col. "W" refers to in his first draft.

Lt.-Cmdr. Kuebler noted that Ottawa's inquiries to the U.S. government about why it was holding Toronto-born Khadr -- then just 15 -- could have provoked the change as the U.S sought to justify the detention. If so, the U.S. government will have effectively lied to the Canadian government.

"Omar is captured and detained, there is pressure from the Canadian government to know about the circumstances of his capture . . . there is a story generated to respond to those allegations," said Lt.-Cmdr. Kuebler. "It turns out we now know that that story was false."

Lt.-Cmdr. Kuebler said when the prosecution provided the defence with both versions of the report, he was told Col. W "updated the document to make it more accurate."

"The point is an official U.S. government document was retroactively altered to be consistent with the proposition that Omar had thrown this hand grenade," Lt.-Cmdr. Kuebler said.

Asked by reporters if the government had "manufactured evidence," deputy chief prosecutor Col. Bruce Pagel said: "No."

The hearing Thursday allowed the defence to formally call for a range of items from prosecutors, including the names of Mr. Khadr's other interrogators and all interrogation notes, correspondence between the Canadian and U.S. governments in the aftermath of Mr. Khadr's capture, and all of Mr. Khadr's statements.

Lt.-Cmdr. Kuebler also seeks a video Canadian officials apparently made of one or more interviews conducted with Mr. Khadr after U.S. authorities transferred him to the Guantanamo naval base. A Canadian Foreign Affairs intelligence officer and an official of the Canadian Security Intelligence Service met with Mr. Khadr in 2003.

Prosecutors argued they'd provided either what they could, or what was relevant to the case, but army Col. Peter Brownbac k, the presiding judge, told them to make a bigger effort to comply.

Lt.-Cmdr. Kuebler told Col. Brownback that while Mr. Khadr had undergone "dozens, if not hundreds" of interrogations, the prosecution has provided notes of only three from a single interrogator - apparently not Sgt. Claus.

Prosecutors said they could not locate two of Mr. Khadr's early statements nor a calendar he compiled.

Lt.-Cmdr. Kuebler seeks to show at an eventual trial that early statements Mr. Khadr made are invalid if interrogations involved coercion. At least one Bagram interrogation took place while Mr. Khadr was still being treated in hospital for extensive battlefield wounds suffered during the firefight.

Lt.-Cmdr. Kuebler said Sgt. Claus "didn't just participate in numerous interrogations of Omar, according to (prosecutor Major Jeffrey Groharing), he did virtually all of them.

"The period of the time that Omar arrived in Bagram to the period when he was taken to Guantanamo Bay is the critical period in terms of the formation of this story," he added. "We're not talking about an able-bodied adult . . . (he was) a wounded 15-year-old child when they hauled him off to Bagram and subjected him to these interrogation methods and techniques."

Sgt. Claus, who was sentenced to five months in jail in 2006 after pleading guilty to maltreatment and assault, was one of 15 U.S. soldiers charged in relation to abuse at Bagram in the latter part of 2002.

He had been one of the final interrogators of an Afghan taxi driver called Dilawar, who'd faced abuse at the hands of a number of U.S. personnel, according to the Army investigation into his death.

A fellow interrogator told the probe that on the day Dilawar died, he saw Sgt. Claus twisting up the back of a hood that he'd placed over the detainee's head.

The same report, first uncovered by the New York Times in 2005, told how Sgt. Claus had made another detainee roll back and forth on the ground kissing a fellow soldier's boots.

Three Afghans Dilawar was ferrying in his used Toyota sedan the day he was arrested, and who were also detained, were later released with letters saying they posed "no threat" to the U.S. forces.