ARMED men have killed eight people in a raid on a Sao Paulo soccer fan club that has close links to a notorious, now-closed prison, Brazilian police said.

Police said witnesses told them that about midnight on Saturday three gunmen stormed the dark and gritty site where Corinthians’ fan group Pavilhao 9 meets underneath a highway overpass. They ordered the victims to lie face down on the ground and shot seven in the head. An eighth man was shot but tried to escape, reached a gas station and was later taken to a nearby hospital where he died.

Detective Arlindo Jose Negrao ruled out a fight between rival fan groups. He would not reveal the motive behind the attack, however, saying that could interfere with the probe.

“Through witnesses, we are already exploring a line of investigation, which is not leading us to believe it was caused by fan rivalry,” Negrao said at a press conference. “We even have possible suspects.”

The victims were having a barbecue at the club at the time and making flags with the soccer team’s colours for Sunday’s anticipated match between Corinthians and Palmeiras. The fan group did not answer several phone calls.

Pavilhao 9 was founded by a group of Corinthians’ fans who played soccer with inmates at Brazil’s Carandiru prison, known widely for a massacre that left 111 inmates dead that was turned into a movie. The prison is now closed.

The Corinthians team did not respond to a request for information but posted the word “Mourning” against a black backdrop on its official Facebook page. Former president of the team and current federal congressman, Andres Sanchez, said on the social network he was “deeply saddened to learn of what had happened at Pavilhao 9, with which I had a strong bond since I was a kid.”

Much of the soccer violence that breaks out in or near Brazilian stadiums is traced to fan clubs. Police often investigate fan groups for ties with drug traffickers.

“It is widely known that criminal organisations are inside of all fan clubs. Organised crime uses these fan groups as a front for their misdeeds,” Juca Kfouri, one of Brazil’s best-known sports commentators, told radio station CBN.

Last year, dozens of members of another Corinthians’ fan club, Gavioes da Fiel, invaded the team’s training centre. Angered by the team’s performance, they attacked employees and grabbed Peruvian striker Paolo Guerrero by his neck, forcing other players to flee into a locker room and barricade themselves until police arrived.