Following his election in 2005, strong controversy erupted when it was revealed by the magazine Der Spiegel that he had worked for the Stasi (the East German secret police) from 1985 to 1990.
Po svojom zvolení v roku 2005 vypukla silná kontroverzia, keď magazín Der Spiegel odhalil, že Heilmann v rokoch 1985 až 1990 pracoval pre Stasi (východonemeckú tajnú službu).