A referee in Brazil is reported to have been decapitated after stabbing one of the players.
According to reports, the referee, believed to be 20-year-old Otavio Jordao da Silva, was tied up, stoned and quartered by an outraged group of supporters - who then put his head on a stake in the middle of the pitch.
The shocking incident is believed to have come after da Silva fatally stabbed a player after being attacked when he made a controversial decision in Maranhao, Brazil, last Sunday.
Eurosport said a group of supporters turned on the referee in revenge.
One man, Luiz Moraes de Souza, 27, has been arrested, according to reports, and police say they are searching for two more suspects.
Brazilian official Valter Costa, who is handling the case, said: "One crime never justifies another crime.
"Actions likes this do not collaborate with the legality of state law."