Riots between "Rockerbandes" in NRW - Germany

Maybe it's because I love a good krimidrama, or police procedural, that this Spiegel article got my interest:
http://www.spiegel.de/panorama/justiz/0,1518,658720,00.html

Amazing that these groups actually controlled street traffic! Interesting comments by Spiegel readers, too, especially comments that, if these groups were gone, a power vacuum would be created that Eastern European gangs would step into. Crikey!

Sheet, I wonder what "rock" bands these groups are into? I'd give those bands a miss, personally.

Rockerbandes = groups of rockers, also known as bikers. This is the Hells Angels vs the Bandidos and these clashes have already caused problems in various bits of Northern Europe including Denmark and the NL. They are also in NRW, and particularly the Bandidos it seems are in Duisburg where they have been running drugs and some of the red-light district there (apparently, they have one).