you may be able to google it. I think it was in West Virginia this weekend. Police were called in.
It happens every year.
All the way back when I had season tickets in Anaheim, and especially during the Raider games, I saw those brawls break out during games... 4 to 8 per game, and vowed I would NOT be bringing my kids to a game. I will NOT go to any Niner games in SF these days... I'm done with attending games there... nothing ever really happened to me... except some taunting, but the last few times I saw opponent fans accosted time after time.. usually in the parking lot but occasionally inside as well. I have NOT been to Levi Stadium... but I have heard ugly rumors that things have not improved.