I think it's pretty obvious to say there's a deep level of corruption in Iraqi society today (maybe it was there in Saddam's time too) and that human life is valued cheaply. Probably doesn't take a lot of money to get someone killed in Iraq.
I have to sympathize with Americans and other foreigners, military and civilians, who have to work in this environment. Very tricky job if you can't take anything, or anyone, for granted. . .