For two decades the al Qaeda affiliated al-Shabab has been fighting an insurgency in Somalia and launching terror attacks in neighboring Kenya. Al-Shabab was responsible for the 2013 attack on the Westgate Mall in Kenya's capital, Nairobi, that killed 67 people, and the 2014 attack on Garissa University in Kenya that killed more than 120 people. Kenya supplies al-Shabab with more "foreign fighters" than any other country. With the help of the Pulitzer Center on Crisis Reporting, Special Correspondent Nick Schifrin met up with three of al-Shabab's Kenyan former recruits. On PBS NewsHour Weekend this Saturday, watch our report on why young men are joining this US-designated terrorist group and what efforts are being made to prevent them from joining.