Career
In 1980 he fought the WBA title but lost to Eddie Mustafa Muhammad. After retiring from boxing, Koopmans became a bodyguard and business partner of underground businessman Bertus Lüske.
In 1980 he fought the WBA title but lost to Eddie Mustafa Muhammad. After retiring from boxing, Koopmans became a bodyguard and business partner of underground businessman Bertus Lüske.
Over the next five years Koopmans defended this title ten times, until losing it to Richard Caramanolis in February 1984.