OTTAWA — A federal inquiry into torture allegations levelled by three Arab-Canadians is facing a crisis of confidence.

Some of the participants complain an obsession with secrecy is undermining the credibility of the proceedings.

Former Supreme Court justice Frank Iacobucci was appointed last December to investigate the cases of Abdullah Almalki, Ahmad El Maati and Muayyed Nureddin.

All three say they were wrongly labelled as terrorists and tortured in Syria or Egypt -- with the complicity of Canadian police and security officers.

The allegations call to mind the better-known case of Maher Arar.

But unlike a previous inquiry into Arar's ordeal, the current investigation has been conducted almost entirely behind closed doors so far.

Lawyers for the three, and human rights groups say they're not questioning the integrity or good faith of Iacobucci.

But they feel he's handicapped by the ground rules set for him by Prime Minister Stephen Harper's Conservative government.

Alex Neve, of Amnesty International, says there is just too much secrecy in the process.

Paul Copeland, the lawyer for Almalki, says he's beginning to wonder whether the inquiry can achieve its chief goal.