The parents of a Paris Saint-Germain supporter beaten to death by fans of the same club have used the one-year anniversary of his death to launch a new appeal for witnesses.
Yann Lorence, 37, was beaten up by fans from a rival fan group prior to PSG's league game against Marseille on February 28, 2010.
He died from his injuries a few days later.
Four men were arrested on suspicion of murder but were released on bail.
"On February 28, it will be one year since our son, Yann, fell beneath the blows of a group of so-called supporters," wrote Lorence's parents in an open letter seen by AFP on Friday.
"We will be in sorrow because, apart from the pain of having lost our child, it appears that some of the perpetrators of his murder have not yet been identified."
They added: "We are convinced that there are still witnesses to the attack on our son who have not made themselves known to the police."