OTTAWA - A former army translator shocked a parliamentary committee Wednesday with explosive allegations against Canadian troops -- including that they killed an innocent Afghan teen and tried to cover it up.

But Malgarai Ahmadshah, former language and cultural adviser to the commander of Canada's Joint Task Force Afghanistan unit, acknowledged that much of his information was second hand and he couldn't offer any proof to back up his claims.

He also wouldn't repeat his allegations outside the committee room, where he was no longer protected by parliamentary privilege.

Inside the room, Ahmadshah claimed Canadian soldiers shot a 17-year-old boy in the back of the head in a village north of Kandahar in the summer of 2007. He said they shot the teen because they thought he had a gun.

He also alleged the soldiers tried to cover up the alleged murder by rounding up men in the village.

"After the Canadian Forces wrongly killed a man, they panicked. They swept through the neighbourhood, arresting people for no reason," he said.

"They arrested 10 men, from about 10 to 90 years old. All the men were taken to Kandahar airfield, where I personally interviewed them with a military tactical-questioner unit.

"None of the detainees were Taliban. None did anything wrong except to be at home when the Canadian Forces murdered their neighbour. Yet Canada transferred all these innocent men to the NDS. I don't know what happened to them."

Ahmadshah later told the committee that he wasn't in the village when the teen was allegedly killed. He said his knowledge of the incident came from interviews with detainees and military documentation.

The Afghan-Canadian man spent 13 months with the military in Kandahar in 2007 and 2008. He was known as "Pasha" to soldiers and Afghans when he served Brig.-Gen. Guy Laroche, commanding officer of Canada's military effort in Kandahar at the time.

Ahmadshah testified that Laroche and other top military brass knew that prisoners handed over to Afghanistan's notorious secret police would be tortured.

"There was no one in the Canadian military with a uniform who was involved in any way, or at any level, with the detainee transfer that they did not know what was going on and what NDS does to the detainees," he said.

He said his military bosses ignored his concerns every time he raised them.

That triggered a fiery exchange with Conservative MP Laurie Hawn, a former air force colonel. Hawn asked if Ahmadshah was calling a succession of Canadian generals liars.

"I don't call nobody a liar," Ahmadshah said.

The scene then broke down into shouting.

Some of Ahmadshah's claims echoe testimony from diplomat whistleblower Richard Colvin who has said that the military continued to hand over detainees even though it knew about concerns of torture in Afghan jails.

It's unclear whether Ahmadshah plans to sue the federal government. Ahmadshah's lawyer, Amir Attaran, wouldn't let the former translator answer any questions about lawsuits inside or outside the committee room.

"We're reluctant to discuss what legal strategy he's pursuing," Attaran told reporters. "There is not a lawsuit at the moment."

Earlier Wednesday, a former foreign service officer told a separate hearing into the Afghan detainee issue about apparently new allegations of abuse.

Nicholas Gosselin, who worked for the Foreign Affairs Department in Kandahar and Kabul, told the Military Police Complaints Commission that he documented eight allegations of abuse between January and August 2008. Those reports came after Canada temporarily stopped handing over detainees to Afghan authorities in November 2007.

But the nature of the eight allegations isn't clear. Gosselin's reports weren't included in the reams of documents before the commission. The strange omission prompted a request from acting commission chair Glenn Stannard for the Justice Department to produce the documents as soon as possible.

It was Gosselin's report of Nov. 5, 2007 -- about a visit to a detention facility -- that led Canada to stop handing over detainees to the Afghans. Transfers resumed in February 2008.

During that 2007 encounter -- Gosselin's first jailhouse visit -- an Afghan prisoner at the jail told Gosselin and a colleague his captors beat him. He showed the Canadians a scar on his hip from the alleged beating.

The prisoner also showed the men the room he claimed he was beaten in. Under a chair, the Canadians saw a length of rubber hose and an 18-inch-long piece of electrical wire. The marks on the prisoner's body seemed to back up his tale of abuse.

Canadian officials stepped up their visits to the jail after Gosselin's report on the incident. He said officials started going to the jail once every two days in November and December 2007.

Visits dropped to about twice a week between January and August 2008, he added.

Gosselin also said the Canadians had a hard time identifying prisoners because the filing system in the jail was "archaic" and there were no photographs of the detainees. Officials had to "check and double-check" all the time to ensure the right prisoner was in custody, he said.

The commission is investigating an allegation from Amnesty International Canada and the B.C. Civil Liberties Association. The groups say military police did not properly investigate officers responsible for directing the transfer of detainees to Afghan authorities, allegedly at the risk of torture.

Transferring prisoners between countries knowing they likely face torture is considered a war crime.