OTTAWA - A Syrian-born man who was held for more than eight years on a national security certificate, only to be released without charge, is suing the federal government for negligence and false imprisonment.

Hassan Almrei, who spent much of the time in solitary confinement, filed the claim Tuesday in the Ontario Superior Court of Justice, citing "egregious failings and errors" on the part of several federal agencies.

"I need to know why all this happened," Almrei said in an interview. "And I need somebody to be held accountable for what happened."

In December, Federal Court Justice Richard Mosley struck down a security certificate against Almrei, arrested in October 2001 on terror suspicions.

The government is reviewing the certificate system, used to deport non-citizens suspected of terrorism or espionage, amid a string of problems with long-running cases.

Adil Charkaoui of Montreal, whose certificate was tossed out last year, is also suing the federal government.

Almrei, 36, is trying to rebuild his life in suburban Mississauga, just west of Toronto. He came to Canada in January 1999 on a false United Arab Emirates passport and attained refugee status the following year.

Mosley said there were reasonable grounds to believe Almrei was a security danger when detained just after the 9-11 attacks -- but no reason to support that belief now.

Almrei, whose claims have not been proven in court, seeks $16 million in damages and any other relief the court may award.

The suit names the Canadian Security Intelligence Service, the RCMP, Citizenship and Immigration Canada and the Canada Border Services Agency. It claims damages for alleged breaches including negligent investigation, false imprisonment, abuse of public office, defamation and violations of Almrei's Charter of Rights guarantees.

A Public Safety spokesman said the government was reviewing the claim. It has several weeks to file a statement of defence.

The government had long argued Almrei's travel, activities and involvement with false documents were consistent with supporters of Osama bin Laden's al-Qaida network.

Mosley found that Almrei had lied to Canadian authorities, provided a forged passport and money to an Arab-Afghan associate who crossed the border illegally, arranged a marriage of convenience for a failed refugee claimant and traded in illicit drivers' licences.

But in his December judgment Mosley criticized CSIS for presenting a dated view to the court without considering whether knowledge about the risk from Islamic extremists had evolved since Almrei was taken into custody in the frantic days following the Sept. 11 attacks.

The government overhauled the security certificate system after the Supreme Court of Canada found elements were unconstitutional in 2007.

Mosley said CSIS and federal cabinet ministers breached their duties of "good faith and candour" to the court by not thoroughly reviewing information on file prior to reissuing the certificate against Almrei under the reworked system in February 2008.

Almrei's statement of claim says many documents the government relied upon in the certificate case were not credible. "For example, as Justice Mosley highlighted, even one of CSIS's own witnesses conceded problems with the Minister's reliance on Wikipedia as a source."

Lorne Waldman, Almrei's lawyer, said Tuesday the Federal Court's strongly worded judgment, which the government did not appeal, was a significant factor in opting to sue.

"Given the tone and the nature of Justice Mosley's decision, I would have expected that there would have been some kind of soul-searching, and some kind of acknowledgment and recognition, that something went horribly wrong in this case," Waldman said.

"But the only thing that we've had so far is absolute silence."

Almrei, who considers Canada home, is seeking permanent resident status. But he says it's difficult to make a normal life because of the cloud of suspicion that follows him.

Almrei said Tuesday he has been treated coolly by others who fear they may find themselves on the federal security radar if they associate with him.

He's dismayed he hasn't received any kind of apology from the government, and says a successful suit would help wipe away any lingering stigma.

"Just acknowledge what happened to me."