French prosecutors have opened an investigation into the death of a 27-year old man who was hit by a projectile at the time of the riots on Saturday, the Marseille prosecutor’s office said on Tuesday.

There was rioting across France following the funeral of a teenager of North African descent, whose shooting by police during a traffic stop sparked nationwide unrest for several days.

Prosecutors said the likely cause of the death in Marseille was a violent shock to the chest from a “flash-ball” projectile as used by riot police, but did not specify who fired or owned the gun. The impact led to cardiac arrest and sudden death.

The man died in the night from July 1 to July 2, while Marseille was engulfed in riots and pillaging, but prosecutors said it was not possible to determine where the man was when he was shot or whether the victim had taken part in the riots.

The biggest flashpoint on Saturday was in Marseille, where police fired tear gas and fought street battles with youths around the city centre late into the night.

Flash-ball guns are designed to be non-lethal riot control weapons that do not penetrate the skin, but their use by police in France is disputed as the projectiles have led to the loss of eyes, head injuries and other trauma.