Mubin Shaikh stared at his own name on the neat, impersonal column of names, birthdates and birthplaces on the secret American cable and blinked. Hard.

"My life is screwed forever," he said. "That's pretty much what it means. That means my life, my children, my family members. They're all screwed."

Shaikh probably understands better than most what inclusion in the cable means. It is a list of people provided by Canada's intelligence agency to the U.S. government — people suspected of what CSIS calls "terrorist-related activity."

The names are now in American databases and watch-lists, with all the consequences that entails.

Along with Shaikh, the secret cable, provided to CBC News by WikiLeaks, names all the people originally arrested in the infamous Toronto 18 case in 2006, some of whom went on to prison on terrorism-related charges.

Shaikh knows the other names on the list well. He was the man who put them away.

A Muslim and Canadian citizen, Shaikh was recruited in 2004 as what CSIS calls a "directed source" — someone assigned to penetrate groups and cells suspected of planning violent attacks. He had volunteered his services after returning to Canada from Syria, where he'd lived for two years.

In 2005, once he'd determined that a large group in Toronto was plotting serious attacks, the case, along with Shaikh, was handed by CSIS over to the Mounties, who launched a criminal investigation.

Star witness

Shaikh became an official, paid agent of the Crown and continued his undercover work for the RCMP, until they rounded up and charged the 18 alleged conspirators.

At that point, Shaikh became the Crown's star witness, testifying in five different criminal proceedings that sent several people to prison.

"It was his evidence that took them all down," Alberta lawyer Dennis Edney told CBC Wednesday night. Edney represented Fahim Ahman, a ringleader who eventually pleaded guilty and remains in prison.

"Most of the warrants for wiretaps that were obtained were obtained as a result of conversations he had with the suspects."

Shaikh proved himself nearly bulletproof to attempts by defence lawyers to discredit him.

There is no doubt of his value to Canadian authorities, or to the Canadian justice system.

And now, described to the Americans by his former employers as "involved in the Toronto 18 conspiracy," he is in at least three American counterterrorism databases, and knows he would be ill-advised to attempt travel to the United States.

"I understand the consequences," he says.

Inclusion in the so-called Visa Viper watch list, to which he was nominated by the U.S. Embassy in Ottawa in September 2009 (and the cable indicates he'd already been placed on another U.S. watch-list), means his name would also have been sent to the wider database of the American National Counterterrorism Centre. And possibly beyond, to other intelligence agencies, some of them rather unsavory, with whom the U.S. government shares intelligence.

"This is just the tip of the iceberg," says Shaikh. "I think someone's got some explaining to do. It just doesn't make any sense, really."

No comment from CSIS

Officially, CSIS has nothing to say about how its own operative was denounced to American authorities.

"We aren't commenting on your story," wrote CSIS public relations person Isabelle Scott in an email. "DFAIT [Canada's Foreign Affairs Ministry] can respond to your questions."

The story, however, has nothing to do with Foreign Affairs and everything to do with CSIS, which had claimed to CBC News earlier this week that it was a careful, responsible steward of information about Canadians.

Long-serving CSIS officials, in private conversations, said that every name handed over to the Americans is carefully vetted by a high-level committee that includes Justice Department lawyers and takes great care to pass on only accurate, credible information about Canadians suspected of "terrorist-related activity."

"CSIS is governed by strict standards and guidelines, including ministerial direction, when co-operating with foreign partners," said the agency Monday, in an official statement issued after queries about naming Canadian citizens to U.S. authorities.

By last night, told that Mubin Shaikh had been named, the agency had circled its wagons.

"They [CSIS headquarters] will not talk about this," said one longtime officer, who said he could not explain Shaikh's presence on the list.

"I cannot believe that name would have come from us," said another security source. "It's just loony."

Shaikh's presence on the list of names means one of two things: Either CSIS blundered badly, which, apart from the attendant embarrassment, will only embolden critics such as lawyer Clayton Ruby, who calls its practice of naming Canadians "abhorrent," or CSIS actually has reason to believe Shaikh is something worse than he seems, which carries legal consequences.

"It takes your breath away," said Mitchell Chernovsky, a lawyer who represented another of the Toronto 18. "It rings alarm bells all over the place."

Both Chernovsky and Edney said they would probably make formal demands to the Crown, asking why they were not told of whatever information led CSIS to denounce Shaikh to the Americans. Defence counsel are legally entitled to disclosure of all such information, in order to prepare their cases.

Croft Michaelson, the federal prosecutor who relied on Shaikh as his main witness, did not return calls, once one of his subordinates was informed about Shaikh's inclusion on the list.

Late Wednesday night, Shaikh said he had made some efforts to contact his old controllers at CSIS.

"I've left some messages," he said, dolefully. "I'm sure this is just a mistake that can be straightened out."

Interestingly, although the U.S. criteria for inclusion on watchlists stipulates that details about those named must be absolutely accurate, lest someone with a similar name is arrested (which has happened in the past), Shaikh's entry is flawed.

His date of birth, Sept. 29, 1975, is accurately logged in the secret American cable. But the cable then states that while he is a Canadian citizen, he was born in India.

In fact, Mubin Shaikh was born at St. Michael's Hospital, in Toronto.