Iraqi authorities have released three of five U.S. contractors, taken into custody for murder charge, due to insufficient evidence, the government spokesman said on Thursday Xinhua reported.
"We have five U.S. detainees, three of them have been released for lack of evidence against them over murder charge, while the other two are still in custody for other crimes," Ali al-Dabbagh told reporters.
The five were arrested on Friday following a predawn raid on their company's office in the Green Zone.
The men were arrested in connection with last month's killing of James Kitterman, 60, who owned a construction company working in Iraq.
On May 22, Kitterman's body was found bound, blindfolded and fatally stabbed in a car in the Green Zone.
The United States and Iraq have signed an agreement which schedules the withdrawal of U.S. troops from Iraq and sets guidelines for the activities of foreign contractors while they remain in the country.
The agreement allows U.S. troops and contractors to be tried in Iraqi courts for only serious crimes that committed while they are off-base and off-duty.
The U.S. combat troops are scheduled to leave Iraqi cities and major towns by June 30, and to completely pullout from Iraq by December 31, 2011.