Audio: the race to save Peter Kassig

The American aid worker was killed by his Isis captors on 16 November. Listen to the Guardian team tell, for the first time, of the daring and extraordinary effort to secure his release, which involved a radical New York lawyer, the US government and the world's most revered jihadi scholar Watch a video explainer on the secret talks to save Peter Kassig The long read: the race to save Peter Kassig