Hassan Diab and his family are suing the federal government over the role Canada played in his extradition to France and years of imprisonment in a French jail — the results of a terrorism probe that ultimately fell apart due to weak evidence.

In a notice of action filed with the Ontario Superior Court, Diab, his wife Rania Tfaily and their two young children seek $90 million in damages.

Diab, a 66-year-old Ottawa university lecturer, was accused by French authorities of involvement in a 1980 bombing outside a Paris synagogue that killed four people and injured more than 40.

Firemen standing by the wreckage of a car and motorcycle after a bomb attack at a Paris synagogue on October 3, 1980 that killed four people. On June 6, 2011, a Canadian court moved to extradite Hassan Diab to France to face prosecution. (AFP/Getty Images)

Diab was arrested by RCMP in November 2008 and placed under strict bail conditions until he was extradited to France in 2014.

Diab was never charged — but he spent more than three years in near-solitary confinement while France investigated his alleged involvement in the terror attack.

Negligence, deceit

The lawsuit accuses the government, Department of Justice lawyers and Rob Nicholson, who served as justice minister under then-prime minister Stephen Harper, of negligence, malicious prosecution, deceit and abuse of process.

Diab and his family are not commenting on the lawsuit. A spokesperson for the Department of Justice would only say officials are "looking into this matter."

The legal action represents an abrupt change of strategy for Diab and his family, who have said all along they didn't want financial compensation. Their longstanding public demands have been for a judge-led public inquiry into Diab's case and reform of Canada's extradition law.

The tipping point seems to be the findings of an department-ordered review of Diab's case by former deputy attorney general of Ontario Murray Segal.

Segal concluded government lawyers acted ethically and followed proper procedures in extraditing him to France.

Diab accused the federal government of perpetrating a "whitewash" by hiring Segal to perform the review instead of appointing a judge to hold a public inquiry with full power to subpoena evidence and cross-examine witnesses.

'Damage control'

Diab boycotted this review, arguing its scope was too narrow and it appeared to be nothing more than a "concerted damage-control effort."

"It's a one-sided report. Its purpose is not to provide accountability. Its purpose is to absolve the Department of Justice of any accountability, and to shield senior officials at the department of any accountability," Diab said last July.

In the notice of claim, Diab seeks $50 million in compensation for himself for malicious prosecution, breaches of his charter rights and punitive damages.

His wife and their two young children seek a total of $40 million for intentional infliction of emotional distress, breaches of charter rights and punitive damages.

Numerous problems with France's case against Diab were evident during the extradition hearings, while others were revealed by CBC News after Diab returned to Canada.

'A weak case'

The Ontario judge who ordered Diab's extradition wrote that France had presented "a weak case; the prospects of conviction in the context of a fair trial seem unlikely."

That proved to be the case. Diab was returned to Canada in January 2018 after French judges dropped his case due to a lack of evidence. French prosecutors are appealing Diab's release.

CBC News later revealed that Department of Justice lawyers helped France strengthen its evidence when the case against Diab appeared to be falling apart.

Fingerprint analysis conducted by Canadian officials showed that Diab's prints did not match prints thought to belong to the suspected bomber. Diab's lawyers say this information was never shared with the extradition judge — denying the defence key evidence of his innocence.

Documents obtained by CBC News also showed that France was aware of — and failed to disclose — fingerprint evidence that helped to clear Diab of involvement in the terrorist attack when it made its formal extradition request to Canada.

"My suffering and that of my family was prolonged by senior officials at the Department of Justice," Diab said last July. "I trusted the government's promise that what happened to me would never happen to anyone else."