Alshabab invested early in having agents everywhere. They have an army of inactive members dormant and waiting to strike any moment. These inactive members are in academia, government, school, business, military. They gather information, monitor activities and when it is the right time, the killer explodes. Who goes first? It is either random or scheduled. It can be both. They will call the inactive member suddenly and tell the person he/she must kill or be killed. Poor terrorist then decides might as well die "going to Jannah" than become dead "kafir".
The Somali nation needs to be saved. This will never end. We need a real plan to clean up the mess.