Hassan Diab
Hassan DiabReuters

A Lebanese-Canadian academic accused over the deadly 1980 bombing of a Paris synagogue is to be freed from custody after the case was dismissed for lack of evidence, legal sources said Friday.

In a decision seen by AFP, the French magistrates leading the investigation said the evidence against Hassan Diab, who was extradited from Canada in 2014, was "not convincing enough" and ordered his immediate release.

Prosecutors later said they would appeal the judges' decision, but one of the sources involved in the case confirmed that Diab was released from prison Friday afternoon.

The October 3, 1980, bombing of a synagogue on Rue Copernic in Paris, which killed four people and injured about 40, was the first fatal attack against Jews in France since the Nazi occupation in World War II.

Diab, a former professor of sociology at Ottawa University, fought his extradition to France to avoid what he said would be an unfair prosecution for a crime he did not commit.

He was accused of planting the bomb inside the saddle bag of a motorbike parked outside the packed synagogue near the Champs-Elysees, where hundreds of people had gathered for Shabbat (Sabbath) prayers.

Diab, the only suspect in the attack, was arrested at his home in an Ottawa suburb in November 2008 at the request of French authorities who alleged he was a member of the Popular Front for the Liberation of Palestine (PFLP).

Evidence against Diab presented by prosecutors included a sketch of the bomber which resembles Diab and the discovery of a passport in his name with entry and exit stamps from Spain, where the bomber is believed to have fled.

There were also testimonies from witnesses that Diab was a member of the PFLP in the early 1980s.

Diab has insisted that he was in Beirut at the time of the attack to take university exams, which witnesses have corroborated.

In their ruling, the magistrates highlighted "a number of elements" that "indicated that Hassan Diab was likely in Lebanon" at the time of the attack.

They said "documents from the Lebanese university" and "testimonials from several students" bolstered Diab's claim that he was in Beirut, and cited the absence of his fingerprints on anything relating to the attack.

"This decision in a terrorism case of such extreme seriousness is exceptional. It shows the rigor and independence of the judges in the face of great pressure," Diab's lawyers said.

The prosecution and judges have been warring over the case for months.

On several occasions, Diab was granted bail only to be taken back into custody after the decisions were overturned on appeal.

France's CRIF Jewish federation said it was "dismayed" by the ruling.

"This release without trial for the main suspect is an insult to the memory of the victims, and a new source of pain for their families," said its president, Francis Kalifat.

Several civil parties have also said they will appeal the decision.

"Given the many discrepancies in this case, it would be best for the appeals court to decide," one of the lawyers representing the parties, Eric Morain, said.