In the latest information clampdown on the Afghan detainee file, the public has been barred from two days of open-door hearings on the matter after the federal government argued that having journalists present would pose a security threat.

Acting on a request from federal government lawyers, the Military Police Complaints Commission barred the public from hearings until Thursday and hung a curtain, or veil, across the doors so that nobody could even glimpse the proceedings inside.

Late Tuesday, the commission promised it would release uncensored transcripts of the hearings as soon as they become available. But the move by the federal Department of Justice to limit public access to the inquiry is part of a pattern of behaviour by Ottawa, which has repeatedly tried to constrain this probe.

The arms-length Military Police Complaints Commission is investigating why Canada continued transferring suspects rounded up by its soldiers to torture-prone Afghan jails even after Ottawa received multiple complaints of abuse.

Over the past two years it has run into a string of roadblocks that Harper government lawyers have set up to delay and severely limit the scope of the probe. Tuesday was the first day of hearings to feature witnesses who have served in the war in Afghanistan.

Two hours before Sergeant Carol Utton, a military police officer, was due to testify Tuesday , Department of Justice lawyers requested the public be cleared from the hearing room. The government then cited the National Defence Act in asking that the hearings be conducted in private for two days: April 6 and April 7.

Elizabeth Richards, a government lawyer, would say only there was something worth keeping secret.

“The justification is it’s sensitive. I can tell you there’s a security concern that’s been raised,” Ms. Richards told The Globe and Mail.

Ron Lunau, lead lawyer for the commission, refused to say exactly why he and commissioners agreed to exclude the public. He said the reasons are confidential and that the commission would issue a written rationale for its decision.

“We’re not blind to the fact this is a public hearing.”

Sgt. Utton, the first witness to testify Tuesday, has previously told commission investigators about the suffering one detainee experienced at Canada’s holding facility in Kandahar. The man was stuck there after Ottawa halted holdovers to the Afghans in early 2007 after a legal bid by human-rights groups to end the practice of transfers.

“It was the most terrible experience to watch this man,” Sgt. Utton told investigators in 2008.

The detainee, who had health problems, was forced to remain in the facility – not built for stays of more than 96 hours – even as temperatures in confinement soared to intolerable levels. “The facility just was not made to hold somebody that long,” Sgt. Utton said in 2008.

The detainee’s screaming and crying – “Who’s feeding my kids? Who’s looking after my wife?” – prompted nearby soldiers to ask the Canadians if they were keeping a dog in there.

“He would scream and yell and climb the cage,” Sgt. Utton recounted at the time. “At one point we had to go in and take the plastic knife from him.”

Paul Champ, a lawyer acting for Amnesty International and the B.C. Civil Liberties Association, said he didn’t formally oppose the move to exclude the public in part because he didn’t want to push back hearings by another one to two days to fight it.

Mr. Champ said the fact the Justice Department agreed to release uncensored transcripts of the testimony was critical to his decision not to oppose the exclusive hearings.

“It was highly unusual but these are not key witnesses.”

However, Mr. Champ said he is concerned Ottawa may try again to seek similar exclusions on future hearing dates and vowed to oppose efforts to bar the public from hearing the testimony of major witnesses.

NDP foreign affairs critic Paul Dewar called the closed-door hearings “farcical” and questioned why Ottawa waited until the last minute to argue there was a security threat.

Liberal defence critic Ujjal Dosanjh said the Harper government’s record of interference in this inquiry suggests it’s trying to hide details from Canadians.