Security officials in Bochum have begun investigating a German soccer hooligan who is believed to have been involved in the rioting by several dozen German and some Slovenian fans over the weekend in Celje, Slovenia during a friendly game between the two countries. The 23-year-old hooligan -- a fan of the Bundesliga club Vfl Bochum -- was identified after a police officer recognized his photograph in a regional newspaper. Police in Bochum confirmed that the hooligan, apparently notorious in Bochum's soccer scene, was known to them for his readiness to resort to violence in the past. On Monday, Slovenian news agency STA reported that charges had been pressed against five German and 20 Slovenian hooligans. According to the Slovenian Interior Ministry, two rival German hooligan groups clashed in downtown Celje on Saturday, smashing shop windows. Slovenian police temporarily arrested 65 persons, 45 of them German. Slovenian authorities estimate that the rioting led to damages worth 12,500 euros ($16,182).