BOGOTA, Colombia — Authorities are still trying to determine the cause of a riot at a soccer game that injured 83 people, including six police.

Among the possibilities: A jealous boyfriend who was angry his girlfriend was flirting with another man.

"This is one of the theories," said Diego Cardona, secretary for sport for the city of Cali, where the brawl occurred. "But when you have so many people drunk, drugged up and looking for a fight, sometimes it's hard to find out what really started it."

The violence flared in the 65th minute of America's match against Deportivo de Cali. Fighting moved from the stands on to the field and then on to the streets surrounding Pascual Guerrero stadium, which has a capacity of about 40,000.

In an effort to contain the escalating riot, heavily armored riot police waded into the stands, a move that seemed to unite the battling fans against the officers, who were pelted with rocks and homemade explosives. The police responded by firing tear gas in to the crowd.

One police officer was stabbed three times and authorities offered a $5,000 reward for information leading to the arrest of the assailant. By night's end, nearly 20 people were treated for stab wounds and more than 60 for bruises.

With the chaos increasing, the referee abandoned the game in the 82nd minute, awarding the victory to Cali, which was leading 1-0.

Yesterday, league officials suspended America coach Diego Edison Umana 11 games and fined him $2,500 for attacking Deportivo counterpart Daniel Carreno.

Carreno was suspended two games and fined $461 for entering the field without the referee's permission.

America also will have to play its next three home games in an empty stadium because of the behavior of its fans.

Cardona had no concrete evidence to prove a lover's quarrel had started the fight, saying it was only one of several explanations police were considering. Another explanation was that a fan with a Deportivo Cali tattoo sat in the America section of the stadium, sparking the melee.

Cardona said fans identified as taking part in the violence will be banned for 10 games from the stadium's notorious southern stand, known for its cheap admission price, home to the Red Barons and site of previous confrontations.

Tickets for other parts of the stadium cost $25. Entrance to the southern stand costs just $2.50.