This incident was caused by street hooligans, not skinheads. Besides it became an international incident by strange panic reaction of president Putin. Maybe Poles should react in same way everytime Polish citizen gets beat up in Russia?
It was skinheads, eye witnesses say it was skinheads, and the media covered it up because they didn't want anyone to realize skinheads about in Poland.
"Eyewitnesses say that the skinheads [the attackers] left the site of the fight on a microbus," Makarenko said. "I don't know many hooligans who are traveling in microbuses."
http://www.rferl.org/featuresarticle/2005/08/8b87a178-6993-48f7-b7e3-f7b9701b49fc.html