Forty-three years ago, a bombing outside a Paris synagogue killed four people and stunned France, prompting huge crowds to protest antisemitism and exposing the country to violence it thought had disappeared with the end of World War II.
On Friday, after decades of false leads, a lack of evidence and legal wrangling, a verdict finally came. The defendant, Hassan Diab, a Lebanese-Canadian sociology professor, was convicted of the murders and sentenced to life in prison.
Judges also issued an arrest warrant for Mr. Diab, who lives in Canada and was tried in absentia. Mr. Diab has long denied any involvement in the attack. In an earlier investigation into the bombing, charges against him were dropped.
The deadly attack, the first on the French Jewish community since World War II, took place in the Rue Copernic, in an upscale western Paris neighborhood, on Oct. 3, 1980.
Explosives placed on a motorcycle parked outside a synagogue, where more than 300 worshipers had gathered to observe Shabbat, detonated early in the evening. The blast collapsed the synagogue’s glass roof, blew out the windows of nearby buildings and knocked over cars.
Four people who were on the street when the bomb exploded were killed — an Israeli journalist, a student passing by on a motorbike, a driver and a janitor. Investigators said the explosives had been set to go off after prayers concluded, when worshipers were leaving the synagogue. But the service was delayed for several minutes and the blast only injured some worshipers.
The attack shocked France, prompting tens of thousands of people to take to the streets in solidarity marches. Neo-Nazi groups were quickly accused of being behind the bombing, and newspapers started to debate a possible revival of fascism, said Clément Weill-Raynal, a French journalist who recently published “Rue Copernic: The Sabotaged Investigation.”
But after a few weeks, the police ruled out the neo-Nazi angle and instead pointed to a splinter group of the Popular Front for the Liberation of Palestine, an armed group that supports Palestinian statehood. Mr. Weill-Raynal said terrorist threats from the Middle East were little known or considered at the time, which “contributed to the slow pace of the investigation.”
It also didn’t help that Raymond Barre, who was the French prime minister at the time, described the attack as having “sought to target Jews” going to the synagogue but ended up killing “innocent French people.” The remark was widely criticized for having anti-Semitic overtones, and Mr. Barre never explicitly apologized.
In 1999, after years of little visible progress, French authorities identified Mr. Diab as a suspect, using police sketches and handwriting analyses. Investigators also produced a passport in his name with entry and exit stamps from Spain, where the assailant was believed to have fled.
Louis Caprioli, a French police officer who worked on the case, told the court this month that he was “convinced that Hassan Diab is the bomber.”
But by the time he was accused, Mr. Diab, who grew up in Lebanon, had migrated to Canada, where he taught sociology after receiving a Ph.D. from Syracuse University. At the request of France, the Canadian police arrested him in 2008, and it took another six years to extradite him.
Mr. Diab spent more than three years in pretrial detention in France before investigating judges decided to drop the charges against him, saying the evidence was too thin.
“We cannot rule out that Hassan Diab is the bomber, but it is difficult to go further,” Jean-Marc Herbaut, the investigating judge at the time, told the court last week.
Mr. Diab was released from jail in 2018 and immediately left for Canada. But three years later, a French court unexpectedly overturned the decision and ordered that Mr. Diab stand trial.
French authorities did not issue an international arrest warrant this time, and Mr. Diab said he would not show up for the trial.
Supported by many groups, including Amnesty International, he has long claimed his innocence, saying he was studying in Beirut at the time of the attack and was a victim of mistaken identity. His lawyer, William Bourdon, urged judges on Thursday “to avoid a miscarriage of justice.”
For victims of the bombing and their relatives, some of whom were plaintiffs in the case, the trial, whatever its conclusion, was a source of relief.
“It’s a good thing that even 43 years later we show that justice is still present,” Bernard Cahen, the lawyer for many plaintiffs, said at the start of the trial. For the victims, he added, “it is the end of a very long ordeal.”
Unlike victims of more recent terrorist attacks, survivors of the 1980 bombing and their relatives received little to no financial or psychological support from the state.
It was not clear whether Canada would turn Mr. Diab over voluntarily or reject an extradition request, given the complexity of the case. Justin Trudeau, the Canadian prime minister, expressed support for Mr. Diab after he returned home in 2018. Mr. Diab can also appeal the decision.
Mr. Cahen, the plaintiffs’ lawyer, sounded a pessimistic note in a recent interview with a French Jewish organization. “Let’s not delude ourselves, Mr. Diab will never be extradited from Canada,” he said.
