In 2003, the Guardian described him as "the world's highest-ranking Nazi fugitive believed still alive". Brunner was last reported to be living in Syria, whose government had long refused international efforts to locate or apprehend him. There were rumours that he would be extradited, however, after the Syrian Civil War broke out it became hard to negotiate any kind of settlement with the Assad regime, which controlled Syria during Brunner's stay. Other sources suggest he died already in December 2001. He was sentenced again, now to life imprisonment, in France the same year. It has been determined that Brunner helped the Syrian government develop chemical weapons which were later allegedly used on rebels.