Hassan Diab's lawyer says his client will boycott a government-ordered review of his extradition to France, arguing the scope of the review is too narrow and appears to be nothing more than a "concerted damage-control effort."

Diab's objections are spelled out in a letter written by his lawyer Donald Bayne and sent to Murray Segal, the former Ontario deputy attorney general tasked with reviewing Diab's case.

"These terms of reference are a disservice to Dr. Diab and to all the suffering he and his family have been put through," Bayne wrote in the letter, which was also sent to Prime Minister Justin Trudeau and Justice Minister Jody Wilson-Raybould.

"Dr. Diab and his family cannot in good conscience participate in what now appears to be little more than a concerted damage-control effort."

Diab, 64, was extradited to France in 2014. Wanted by French authorities in connection with a 1980 bombing outside a Paris synagogue that killed four and injured dozens, Diab spent more than three years in near-solitary confinement while France investigated his alleged involvement in the terror attack.

Diab was never charged. He was returned to Canada in January 2018 after French judges dropped his case due to a lack of evidence.

Hassan Diab, centre, leaves a press conference with his lawyer, Donald Bayne, left, on Parliament Hill in Ottawa on April 13, 2012. The Ottawa professor was ordered extradited to France by the Canadian government. (Patrick Doyle/The Canadian Press)

Diab and his supporters have demanded a judge-led public inquiry to examine the handling of his case by Department of Justice officials.

They also want an examination of Canada's extradition laws, which allowed Diab to be sent to France on the basis of what the extraditing judge called a "weak case" and left Diab to languish in a maximum security prison for more than three years.

Rights groups such as Amnesty International and the B.C. Civil Liberties Association (BCCLA) also called for a public inquiry after CBC News revealed the steps Canadian government officials took to help secure Diab's extradition.

But Wilson-Raybould rejected the calls for a public inquiry and instead asked Segal to conduct an external review of the case.

"Mr. Segal will be given the tools, access and discretion necessary to conduct a thorough and independent review of the case," Wilson-Raybould said in a statement announcing the terms of the review in early July.

Wilson-Raybould's spokesperson David Taylor released a statement saying essentially the same thing when asked to respond to Diab's boycott.

"This independent external review is being led by Murray Segal. Mr. Segal has been given the tools, access and discretion necessary to conduct a thorough review of the case," Taylor said in his statement.

Diab doesn't agree. According to Bayne's letter, he objects to the fact that Segal won't assess Canada's extradition laws and will be the only person allowed to question witnesses or see documents connected to the case.

"The real issues will not be addressed, no problem with existing law will be identified, no Ministry of Justice personnel will be embarrassed or sanctioned," Bayne wrote.

Minister of Justice and Attorney General of Canada Jody Wilson-Raybould rejected calls for the public inquiry and instead asked for an external review of the Diab case. (Adrian Wyld/Canadian Press)

Bayne wrote that the terms of reference of the investigation "compel Dr. Diab and his family to the conclusion that the minister has no serious intention to examine the problems in Canadian extradition law and procedure."

"He and his family sincerely regret that they are compelled to this conclusion as they wished very much to be an active participant in a public inquiry process that would be beneficial to all Canadians," the letter adds.

In his letter, Bayne says he has "deep personal and professional respect" for Segal and that the decision to boycott is about the terms of reference and not Segal personally.

In a statement to CBC News, Segal defended the review and encouraged Diab to reconsider his boycott.

Murray Segal is a former Ontario deputy attorney general who has been asked to review Diab’s case. (CBC)

"The terms of reference include access to people and documents. The materials and access will help support a thorough examination," Segal said. "I have asked (Bayne) to reconsider as the review would be immeasurably assisted by Dr. Diab's and (Bayne's) input."

Segal spent decades holding senior positions in the Ontario public service before leaving for the private sector, where he has worked as a lawyer, mediator and consultant.

He has led a number of high-profile reviews, most notably the independent probe of the actions of Nova Scotia police and public prosecutors in the Rehtaeh Parsons case. He also has conducted reviews of CSIS and the Criminal Law Branch of British Columbia.

Rights groups renew calls for public inquiry

Amnesty International and the BCCLA have renewed their demands for a public inquiry into Diab's extradition due to similar concerns about the scope of the external review established by the government and the tools available to it.

A letter sent by Amnesty and the BCCLA to Wilson-Raybould on July 16 argues that "a full picture of why Dr. Diab was sent from Canada to France may not emerge from this review," adding that it will assess only whether the law and Department of Justice practices and procedures were followed.

"With respect, this is inadequate and, in fact, entirely misses one of the main reasons this review is necessary," the letter states.

The human rights organizations also argue that current or former officials in the French government who might be able to shed light on French conduct leading up to Diab's committal for extradition might not be interviewed as part of the review.

Documents obtained by CBC News show 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.

The letter from the human rights organizations adds that France may have a strong interest in objecting to the production of certain documents for the external review in order to obscure its conduct. The letter asks that all relevant documents and evidence in Canada's possession be provided to Segal, regardless of France's preferences.

"The strong public interest in a full understanding and accounting of the events in Dr. Diab's case, in our view, must supersede international relations concerns."

During an end-of-session news conference in June, Prime Minister Justin Trudeau expressed confidence that an external review would be an adequate mechanism to investigate any issues with the Diab extradition.

"I think for Hassan Diab, we have to recognize, first of all, that what happened to him never should have happened," Trudeau said. "This is something that obviously was an extremely difficult situation to go through for himself, for his family, and that's why we've asked for an independent, external review to look into exactly how this happened and make sure this never happens again."

Diab's case remains before the French courts. France has appealed the January decision to release Diab from prison. Three French magistrates in Paris were expected to rule on the appeal on July 6. However, the sudden appearance of new evidence has delayed the decision until late September.