[freespirited]

No word on whether the 'youths' were students at the school, or whether they had any basis for trying to attend that particular school dance.

Apparently the answers are no and no. From another article:

"The whole thing started when a group of young adults were not permitted to enter a junior high school dance. They got angry and started throwing rocks through the school windows," Eriksson said.

http://news.smh.com.au/breaking-news-world/riots-rock-stockholm-suburb-police-20100609-xwvv.html

[Will88]

"The whole thing started when a group of young adults were not permitted to enter a junior high school dance.

I hope that's that case. Every Euro nation (and the USA and Canada, and Australia and NZ) is loaded with self-loathing white people who will excuse anything from a minority if they can find any possible basis for it, no matter how flimsy.