BBC News
By Olivia Davies
media captionReporter Olivia Davies went to school with brothers who later abandoned their life in Wales to become extremists in Syria
I went to sixth form college with both Nasser and Reyaad, and Aseel had gone to my school.
I recently travelled to Syria for BBC Panorama to try and speak to Aseel and to find out why they left Cardiff to join such a brutal organisation.
Aseel Muthana
image captionAseel Muthana is in jail in north-east Syria
Aseel was pleased to see me. He's spent two years in a crowded cell in north-east Syria. He is being held by the Kurdish forces who captured Islamic State group members at the last bloody battle of Baghuz.