On July 14, a man radicalized by ISIS attacked a crowd in Nice, France during a fireworks display for Bastille Day. 84 were killed in the attack.

MSAKEN, Tunisia (AP) — The uncle of the truck driver who killed 84 people on the French Riviera says his nephew was indoctrinated about two weeks ago by an Algerian member of the Islamic State group in Nice, as anti-terrorism authorities question potential accomplices in the devastating attack.

France held a countrywide moment of silence Monday to remember the victims, but the national mourning was punctured by anger and political division. Crowds massed on the Riviera seafront booed the visiting prime minister, whose Socialist government is coming under increasing criticism from the public and the conservative opposition for failing to prevent the Bastille Day carnage.

IS claimed responsibility for last week’s attack, though Interior Minister Bernard Cazeneuve said Monday that investigators have found no sign yet that attacker Mohamed Lahouaiyej Bouhlel had links to a particular network.

The driver’s uncle, Sadok Bouhlel, told The Associated Press in Tunisia that given Bouhlel’s family problems — he was estranged from his wife and three children — the Algerian extremist “found in Mohamed an easy prey for recruitment.”

French officials couldn’t confirm Monday that attacker Bouhlel had been approached by an Algerian recruiter, saying that the investigation is ongoing.

Bouhlel’s rapid radicalization has puzzled investigators. Friends and family said he hadn’t been an observant Muslim in the past. Cazeneuve said Monday on RTL radio that the driver may have been motivated by IS messages, but not necessarily coordinating with a larger network.

“Mohamed didn’t pray, didn’t go to the mosque and ate pork,” said the uncle, a 69-year-old retired teacher, in the driver’s hometown of Msaken, Tunisia. The uncle said he learned about the Algerian recruiter from extended family members who live in Nice.