A Morocco-born Montreal man the Canadian Security Intelligence Service believes was once an al-Qaeda sleeper agent is on a cross-country speaking tour meant to show what he calls "the face of the monster."

In this photo taken on June 25, 2008, Adil Charkaoui flashes a victory sign as he leaves a news conference in Montreal. (Ryan Remiorz/Canadian Press)

Adil Charkaoui was detained under an immigration regulation known as a security certificate six years ago. He was later released but had to agree to put up $50,000 bail and remain under electronic surveillance.

The tour, which began in Kingston, Ont., four days ago, is an attempt to rally public support to have the security certificate law abolished and clear his name.

"This law is a medieval law. In a country like Canada, it is shameful," he told about 100 people at a union hall in Toronto on Thursday.

There were notes of humour as well as bitterness as Charkaoui regaled his audience with tales from what he calls his "nightmare."

Well before the deadly Sept. 11, 2001 attacks on U.S. targets, CSIS agents had Charkaoui under surveillance. They had seen him associating with Muslim men in Montreal they suspected were supporting Islamist extremists in North Africa.

He said three days after 9/11, two CSIS agents wearing sunglasses walked into the pizza restaurant he owned and, according to Charkaoui, asked him this question:

"Where is Osama bin Laden hiding?"

"I told them he was in the basement, having a siesta," said Charkaoui, a permanent resident of Canada who has denied any connection to terrorism.

He said soon after that visit, someone began cutting the phone lines to his restaurant at peak hours, eventually driving him out of business. Then in 2003, he was detained under a security certificate, which denied him the right to see much of the evidence against him.

"I think it is very important for me to show the face of the monster," Charkaoui said.

He spent 21 months in prison before a Quebec judge released him with conditions. Until recently, he was not allowed to go anywhere without his mother present.

Charkaoui is one of five suspects who were issued the security certificates under a federal law created to deport non-citizens with suspected ties to terrorist organizations.

The others, also released on house arrest after periods of detention, include Mohammad Mahjoub, Mahmoud Jaballah, Hassan Almrei and Mohamed Harkat.