Al Qaeda in Iraq and their network of suicide and car bomb cells have been the greatest threat to security in Baghdad, particularly since the implementation of the Baghdad Security Plan. Suicide attacks are aimed at Shia neighborhoods and markets in an attempt to reignite the sectarian murders, as well as at security forces in an attempt to break the will of the Iraqi police and soldiers. Over the past five days, Iraqi and U.S. forces have put a big dent in the leadership of a suicide and car bomb cell in Adhamiyah, as well as an al Qaeda leader in Abu Ghraib.
It always fascinates me that the leaders of the "insurgents" would allow themselves to be captured alive rather than going out with a "bang" like the suicide/martyr attacks they've ordered of others.