NICE, France (Reuters) - French police questioned ten people on Monday suspected of providing material assistance, directly or indirectly, in the truck attack on a crowd of people in Nice last July which killed 86 people, a judicial source said.

The attack, carried out by a Tunisian who swerved his truck through crowds gathered to watch a fireworks display on France’s national day on July 14, was claimed by Islamic State.

The attacker was shot dead by police at the scene.

“We are talking here about a logistical trail, of people who could have helped in carrying out the attack,” the source said, indicating that police were investigating who may have supplied the attacker with weapons.

The ten being questioned, who can be held in custody for up to four days, included several people from eastern Europe, the source said. Several others were arrested in the aftermath of the attacks also on suspicion of being part of the attacker’s logistics’ network.

While Islamic State claimed the attack, authorities say they have yet to find evidence that the 31-year-old attacker had any actual links to the militant group.