Defence Minister Peter MacKay is dismissing an Afghan translator's allegations that the Canadian military tried to cover up the fatal shooting of a 17-year-old Afghan civilian in October 2007 as unsubstantiated "drive-by smears."

Former translator Ahmadshah Malgarai speaks to the media after testifying Wednesday at a special committee meeting on the Canadian mission in Afghanistan on Parliament Hill. (Blair Gable/Reuters)Ahmadshah Malgarai alleged to MPs in Ottawa on Wednesday that the military "panicked" and rounded up half a dozen Afghans between the age of 10 and 90 in a village north of Kandahar after the shooting of a young man sleeping on the roof of a compound.

But in response to opposition calls for a public inquiry, MacKay insisted Thursday the Canadian Forces investigates all substantiated allegations of abuse.

"Our troops certainly deserve better than drive-by smears and unsubstantiated allegations," the minister told the House during question period.

In an exclusive interview with the CBC's Evan Solomon on Thursday, Malgarai said he could back up his claims and lead MacKay and the government to the witnesses of the alleged incident and name the family of the young man killed.

"If he wants me to prove it, give me access to the information and I'll lead them to it," Malgarai said. "Or issue a visa, I'll bring the witness."

Malgarai also claimed Canadian officials were well aware that detainees transferred into the custody of the Afghan National Directorate of Security (NDS) were tortured, calling it "interrogation, Afghan-style" and "subcontracting torture." He told the committee any statement to the contrary by military and political leaders is "a lie."

Malgarai, a Canadian citizen born in Afghanistan, said the soldier who allegedly shot the man in the back of the head mistakenly thought he had a pistol.

But Malgarai, who served as adviser to the former Joint Task Force commander in Afghanistan from June 2007 to June 2008, admitted to MPs on the committee that he did not witness the alleged shooting, but said he was present for the interrogation of the detained men afterward. In his testimony, he also named military officials involved in the investigation and said one of the soldiers called the shooting "murder."

Liberal foreign affairs critic Bob Rae seized upon Malgarai's allegations during Thursday's question period to repeat the opposition's calls for the government to call a full public inquiry.

"There is no other place for these allegations to go," Rae told the House.

MacKay replied that Malgarai himself admitted he did not witness the alleged shooting and had no specific evidence to back up his allegations.

"When specific allegations are brought forward, we have forums, we have investigations, and we have the ability to look into them, but in yesterday's testimony there was no specific evidence offered, by his own admission," MacKay said.

Responding to Malgarai's allegations late Wednesday, the chief of defence staff, Gen. Walter Natynczyk, issued a statement saying the Canadian Forces will investigate the matter "appropriately" but that the military would not be led astray by "innuendo."

"The Canadian Forces hold themselves to the highest level of professional conduct," Natynczyk said.

'Now they don't need my service'

Malgarai, who goes by the name Pasha, has alleged the Canadian government is trying to punish him for speaking out against sending detainees to the NDS, saying someone leaked information to the Taliban, who then issued death threats to his family.

He claimed that he personally asked MacKay to help get his family out of Afghanistan, but his request was refused.

"They needed me, and I was Pasha; I was gratified," he told the CBC's Solomon on Thursday. "Now they don't need my service. That's the name of the game with the Canadian Forces."

But Malgarai denied the alleged leak or MacKay's refusal was the reason he was making his allegations.

In his call for a public inquiry, NDP Leader Jack Layton said it was clear from several witnesses' testimony at the parliamentary committee and the Military Police Complaints Commission's own probe into Afghan detainee transfers that "everybody knew" torture by the NDS was "widespread."

"Our troops deserve better than this, Mr. Speaker," Layton said.

MacKay said the opposition parties should show more support for Canadian troops, who are doing an "exceptional job under difficult circumstances."

Liberal MP Ujjal Dosanjh angrily accused the government of "cowardice" for not calling an inquiry on the Afghan detainee file, noting that Natynczyk launched an investigation into Malgarai's allegations just hours after the witness's testimony.

A defiant MacKay hit back at Dosanjh, saying he wished the lawyer and former B.C. premier's questions would reflect the "great work" of Canadian soldiers on behalf of the country, instead of "more rhetoric, more sound and fury, more unsubstantiated allegations."

"He should stop disparaging their name, their work, stop making allegations, insinuating that they are war criminals," MacKay said. "That is despicable, detestable evidence."

Speaking outside the House of Commons, NDP defence critic Jack Harris said MacKay is wrong to dismiss the testimony of Malgarai, who "connected the dots in a way that they've not been connected before."

"We're getting to the point where the denials are hollow," Harris told reporters.