The owners of Sullivan Stadium in Foxboro,...

The owners of Sullivan Stadium in Foxboro, Mass., have started an investigation on why regular beer was sold at last Sunday’s New England Patriots’ game. Only low-alcohol beer is supposed to be available at concession stands.

After the game, a 34-23 victory over Cincinnati that put the Patriots into the NFL playoffs, fans flooded the field, tore down a goal post and left the stadium with part of it. Five fans were injured when a section of the goal post touched a power line.