During the 1980s and '90s, a number of riots occurred that were related to longstanding racial tensions between police and minority communities. The 1980 Miami riots were catalyzed by the killing of an African-American motorist by four white Miami-Dade Police officers. They were subsequently acquitted on charges of manslaughter and evidence tampering. Similarly, the six-day 1992 Los Angeles riots erupted after the acquittal of four white LAPD officers who had been filmed beating Rodney King, an African-American motorist. Khalil Gibran Muhammad, the Director of the Harlem-based Schomburg Center for Research in Black Culture has identified more than 100 instances of mass racial violence in the United States since 1935 and has noted that almost every instance was precipitated by a police incident.