paris britain oxford university say one professors prominent swiss muslim intellectual tariq ramadan take leave absence two women file complaints france allege rape university consistently acknowledge gravity allegations professor ramadan emphasise importance fairness principles justice due process oxford university say statement agree leave absence imply presumption acceptance guilt allow professor ramadan address extremely serious allegations make categorically deny add geneva-born academic grandson hasan al-banna islamist thinker activist found muslim brotherhood deny allegations make two women include author henda ayari say rap muslim convention 2012. paris prosecutor last month open preliminary probe accusations follow ayari complaint ramadan file complaint slander tuesday ramadan publish facebook page french statement oxford university add welcome university handle situation separately prosecutors monday open investigation death threats twitter satirical weekly charlie hebdo front page cover publish rape accusations targetting ramadan twelve people kill magazine headquarter january 2015 first wave militant attack leave 240 dead past two half years oxford islamic academic take leave rape allegations