1,000 participants was arranged in Prenzlauer Berg by supporters of FC Berlin after the match against HFC Chemie on 10 November 1990. The demonstration was supported by the recently founded Fanprojekt Berlin. Also professional FC Berlin players such as Waldemar Ksienzyk participated in the march. The demonstration received support from politicians such as Lena Schraut from the Alternative List and from left-wing activists, notably from the occupied houses near Senefelderplatz at the Schönhauser Allee. The friendly match between East Germany and West Germany that was planned to be held on the Zentralstadion in Leipzig on 21 November 1990 was cancelled for security reasons and due to the tense situation among football supporters after the shootings. An investigation against ten police officers was opened, but closed in April 1992. The exact circumstances around the death of Mike Polley were never fully clarified. Stadium attendance collapsed in 1990. Many supporters stopped attending matches after the Peaceful revolution, as the best players were sold off to clubs in West Germany, sports performance slumped, tickets prices rose, mass unemployment spread and hooligans had come to dominate the stands. Some shifted their focus to ice hockey instead. The average league attendance of the 1990–91 NOFV-Oberliga was by far the lowest in the league history. BFC Dynamo was hit particularly hard by the decline. Average attendance at BFC Dynamo had dropped from 8,385 in the 1988–89 season to 1,076 in the 1990–91 season. Ordinary supporters had disappeared. Only young supporters remained in the stadium at FC Berlin in 1990 and 1991. The violent faction of FC Berlin would come to shape the entire 1990–91 season. Matches involving FC Berlin were all security matches. A group of 500–600 supporters of FC Berlin travelled with a special train to Rostock for an away match against F.C. Hansa Rostock on 16 March 1991. The police did not manage to control the situation despite a record strong presence of more than 600 officers. Riots broke out in central Rostock, where supporters smashed shops, demolished cars and attacked people. Supporters without tickets stormed the Ostseestadion and there were fights with supporters of F.C. Hansa Rostock around the stadium. Riots at the train station after the match had to be suppressed by the police with tear gas and water cannons. The damage was again extensive. Up to 17 shops at the Wismarischen Straße were smashed and looted, the train station was devastated