OTTAWA - Diplomat Richard Colvin says his repeated warnings about war prisoners in Afghanistan facing a "high risk" of torture at the hands of their Afghan captors fell on deaf ears.

In a second round of eagerly anticipated public testimony Tuesday, Colvin told the Military Police Complaints Commission that he and his colleagues in Afghanistan knew of "patterns of risk facing our detainees."

The diplomat, whose testimony at a parliamentary committee last year caused a sensation, said he had credible information about abuse within a month of arriving in Kandahar in the spring of 2006.

"It wasn't that (a detainee) has been mistreated," Colvin said. "It was that a group of detainees transferred by Canada were vulnerable of mistreatment or being mistreated."

He warned of the problem in several emails and he again raised the detainee issue during a March 2007 meeting in Ottawa between government officials.

"You know the NDS tortures people. That's what they do," Colvin said he told the officials. "If we don't want people tortured, we shouldn't give them to the NDS."

That's when he says the note-taker put down her pen.

It was this sort of hear-no-evil, see-no-evil attitude that Colvin says he felt he was "up against."

Colvin said he omitted the word "torture" from his emails because he had to be careful how he phrased things, putting things in code.

"I'm alerting the readership that these words are standing in for words which might, in my view, include 'torture,"' he said.

Justice Department lawyer Alain Prefontaine later shot back: "If this is in code, you're not giving the reader the de-coder ring that goes along with it."

Colvin also revealed that weeks -- or even months -- passed before Canadian officials told the International Committee of the Red Cross about detainees Canadians handed over to Afghan authorities.

And information such as a name or home village about detainees passed to the Red Cross was insufficient, Colvin said.

"They couldn't find our people because so much time had passed and the information was inadequate."

He said Red Cross workers "were quite forceful" when the complained to him about how long it was taking the Canadians to let them know about turned-over detainees.

Officials with the NATO-led International Security Assistance Force voiced similar concerns about being left in the dark, he added.

He told the commission an ISAF colleague was surprised to learn Canadians had taken Afghan prisoners. The diplomat said an official complained that "getting information from the Canadians is like getting blood from a stone."

Meanwhile, Colvin said rumours persisted that Kandahar's former governor, Asadullah Khalid, kept secret jails.

Colvin also detailed other allegations swirling around Khalid, which included suggestions the governor was a heavy user of drugs with a predilection for young girls.

"I had a lot of negative information on Mr. Khalid," Colvin said.

"Generally, among people we met, it was quite hard to find someone who had a good thing to say about him."

Colvin told a parliamentary committee last year that Canada ignored warnings of torture involving detainees in Afghanistan.

At the time he said nearly all prisoners captured by Canadian troops in 2006 and 2007 were tortured by Afghan authorities.

Generals, senior federal officials and cabinet ministers have denied the charges.

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.