Nairobi, Nov. 25 -- Hussein Mustafa had arrived in Eastleigh with a sewing machine. His customers, at a rented stall in the Eastleigh Shopping Centre, thought he was a tailor struggling to eke out a living. But he was on a mission.

Mustafa's sewing machine masked his intentions. Every morning, mostly without fail, he would open the stall and take orders - like any tailor would. But he was in Eastleigh for a purpose: an evil assignment that culminated in the 18-year sentence he is now serving for assisting the Westgate terrorists.

As the terrorist's tailor, Mustafa was to design and make the grenade and magazine vest jackets that were to be used by the terrorists on the day of the attack. He was to make sure the jackets could hold grenades...