Allegations are emerging that two Canadians might have been involved in the torture of one of Britain's last remaining residents at Guantanamo Bay.

Binyam Mohamed, 31, claims to have been tortured after being arrested in Pakistan in 2002. And he alleges that Britain was complicit in the torture and Canada may have also had a role in his rendition.

Mohamed was flown to Morocco after his arrest and interrogated. He alleges that after refusing to speak with Americans, a third-party intermediary, who called herself "Sarah, the Canadian," was brought in.

Zachary Katznelson, Mohamed's lawyer, spoke to CBC News exclusively on Thursday and shared sections of a diary his client says he kept during the ordeal.

"If you don't talk to me, the Americans are getting ready to carry out torture," Mohamed wrote that Sarah told him. "They're going to electrocute you, beat you and rape you."

Mohamed alleges he was beaten and cut with razor blades, including hundreds of times on his genitals, while he was held.

The diary documents Sarah, who is described as about 30 to 35 years old, speaking with Mohamed and warning him to talk before leaving him to be tortured, Katznelson said.

"[It was] absolutely brutal, horrific torture," Katznelson said. "Anyone who played a role in that — big or small — has to answer criminally and morally.

"It's a violation of the convention against torture for any country to participate in such an event, and Canada would have something to answer for," he said.

CBC's Adrienne Arsenault reports that Mohamed also claimed he was later interrogated for about an hour by another woman who spoke French and said she was a Canadian. He described that woman as red-haired and going by the name of Fifi, Arsenault said.

Katznelson said Mohamed's legal team has asked Canadian officials about the identity of the two women but a reply has never been received.

No knowledge of allegations

Late Thursday, a government spokesperson issued a statement saying the Department of Foreign Affairs had no knowledge of the allegations but has in the past objected strongly to instances where foreign agents claimed to have links to Canada.

Given that Canada's overseas reputation is on the line, the issue should be pursued aggressively through political, diplomatic and intelligence channels, said Thomas Quiggin, a Carleton University professor who specializes in intelligence.

Even if someone was pretending to be Canadian, those concerns don't go away, Quiggin said.

"If it's Americans doing this, we would expect to have a diplomatic protest to the Americans over this," said Jack Harris, the New Democratic Party's national security critic.

Documents not being released

Mohamed's legal team has sought the release of dozens of classified documents about his treatment from 2002 to 2004, when he was transferred to the U.S. naval base at Guantanamo Bay, Cuba.

Britain has refused to release 42 documents related to Mohamed, following a court ruling and statements from the U.S. government that doing so may harm the countries' intelligence-sharing agreements.

The U.S. has also refused to provide classified documents — which are alleged to be related to Mohamed's torture — to his lawyers.

Mohamed was born in Ethiopia and moved to Britain at age 16, where he was granted residency.

He later converted to Islam and travelled to Pakistan and Afghanistan, where U.S. officials allege he fought alongside Taliban forces and later attended al-Qaeda training camps.

He affirms that his interrogators in Morocco asked him questions about things that only British intelligence agents could have known.

Britain has denied it had knowledge of Mohamed's alleged torture or abuse. It also has said it only learned that Mohamed had been sent to Morocco to be interrogated a year after he had already been in Guantanamo.

Mohamed was accused of plotting to set bombs. But in October the Pentagon dismissed all charges against him; he says he only confessed after being tortured.

With files from Adrienne Arsenault