The decision to expel Blackwater Worldwide out of Iraq was prompted by “improper conduct and excessive use of force” in a shooting that killed 17 Iraqi civilians and injured dozens of others, in September 2007, according to interior ministry spokesman, Major General Abdul-Karim Khalaf.
The 17 Iraqis were killed when guards protecting a convoy of US diplomats opened fire in Nisour Square, in Baghdad.
Wikipedia: Blackwater Baghdad shootings Nisour Square
SOURCE: guardian.co.uk US security firm Blackwater faces expulsion from Iraq