<sod >The man, who was later killed by police, approached the two officers from behind and stabbed them several times, Philippe Dulieu, spokesman for the Liege prosecutor's office said.< eod>< sod > The man, who was later killed by police, approached the two femaleÂ officersÂ from behind and stabbed them several times on aÂ boulevard in the centre of Belgium's third-largest city, around 30 miles from the German border.< eod>