Minneapolis police say they arrested 23 people for disorderly conduct and vandalism during Saturday night's melee at the University of Minnesota. They say six officers were injured. Rambunctious fans smashed street lights, jumped cars and set fires after the men's hockey team won the NCAA championship. The university is still trying to tally up the damage.

	Minneapolis Police Chief Robert Olson defends his officers' handling of a campus disturbance Saturday night, which started out as a celebration of the Gopher hockey team's victory in the NCAA national championship. Police used pepper spray and tear gas to disperse the crowd after unruly fans began lighting fires and throwing rocks and beer bottles. (MPR Photo/Brandt Williams)

An estimated 600 people clogged streets near the U of M and Dinkytown Saturday night, celebrating the hockey team's win over Maine - and the team's first national championship in 23 years. But after police opened up the streets, Minneapolis Police Chief Robert Olson said the crowd turned ugly, lighting fires and hurling rocks and beer bottles.

"When you're in the middle of a riot situation involving assault, arson and destruction of property, it's never a pretty sight. In those situations arrests are rough -there's no question about it," says Olson.

Police in riot gear sprayed mace and pepper spray into the rowdy fans. Some of those fans said police used a heavier hand than was necessary. Olson was asked about a televised videotape that appeared to show police roughing up a rioter lying on the ground.

"Just because someone's lying on the ground does not mean they're not dangerous," Olson said. "When you're making arrests in a riotous situation, you need to make your arrests quickly...and get them out of there. That means they need to comply with your orders to cease and desist, and put their hands behind their heads and be handcuffed."

Olson says there have been no complaints filed alleging police brutality related to the event.

"When you're in the middle of a riot situation involving assault, arson and destruction of property, it's never a pretty sight. In those situations arrests are rough. " - Minneapolis Police Chief Robert Olson

The University of Minnesota's vice president for Campus Life, Robert Jones, said he was disappointed that a few students allowed their exuberance for the celebration to get out of hand. Jones says the U doesn't know how many students were responsible for the damage, but he says his office will investigate.

"What we plan to do is look at videotape, look at police arrest records and reports, and check that against our student registration database. There's news media and others that have videotape of what was going on," Jones says.

Destructive fan behavior has become quite common in recent years. Soccer fans throughout the world are known for their riots even during games - which at times result in deaths. At the University of Maryland last week, fans celebrated the basketball team's national championship by ripping up street signs, smashing store windows and lighting fires. So what is it about sports championships that cause fans to erupt into riotous mobs?

Charles Stangor, a professor of social psychology at the University of Maryland, says it's a combination of things. Stangor says it's one of copycat behavior based on previous celebrations at other schools, a lack of inhibitions due to alcohol and a crowd mentality. He says people in a crowd tend to want to identify with the group, particularly if that group represents a winning school.

"A lot of desire to be part of the group, to express your membership in the group, your devotion to the group and your identity with the group in general. So you look around and you see other people behaving in a certain way, and you're likely to copy that behavior," Stangor says.

University officials say they should have estimates of the damage by the end of the week.

University of Minnesota Vice President Robert Jones' statement on weekend disturbance