Another picture can be found at http://softkenya.com/kenya-news/wp-content/uploads/2013/09/Abdul-Haji-and-a-fellow-police-offider-in-the-mall.jpg and http://www.sundaytimes.lk/130929/sunday-times-2/hero-of-kenya-massacre-revealed-64065.html
I also found this one by the BBC which Cropped OUT the weapon. http://news.bbcimg.co.uk/media/images/70157000/jpg/_70157979_abdul_motherbaby_reuters.jpg
Grip looks too thick for the Sig 220. Might be a Beretta 380 (84FS)