He was taken to the group's base in Raqqa, Syria, and then to their most highly prized asset in Iraq - the northern city of Mosul.
Mr Todenhofer is no stranger to the risks that come with bearing witness to conflict. From Afghanistan to Iraq and Syria he has consistently visited and written about conflicts which have drawn in the US and its allies. He has become a vocal critic of American foreign policy and military interventions.
His own experience has included years in the legal profession and as a centre right member of the German Parliament. But now he's best known as a peace advocate prepared to talk to anyone with a stake in contemporary conflicts.
He talks to Stephen about what motivates young Muslims from the West to join Islamic State and what life is like for those who live under IS control.
WIKI: Jürgen Todenhöfer »
