From courtrooms and prisons to rehab centres and martial arts training. We look to Europe, Iraq, Central Asia and Saudi Arabia to investigate how they are dealing with Islamic State militants.

The defeat of Islamic State in Iraq and Syria has raised a new, global challenge. While Iraq is funnelling huge numbers of Islamic State suspects through its courts, thousands of foreign fighters are returning to their home countries. What is happening to former IS fighters?

(Photo: A man takes down a poster of the IS militant group's flag. Credit: Getty Images)