Government officials have revealed that the Blackwater forces involved in last month’s deadly shooting in Baghdad have been secretly given immunity by the State Department. Officials said the immunity deal has undermined efforts to prosecute anyone from Blackwater for the deaths of the 17 Iraqi civilians killed on Sept. 16. The immunity deal has also delayed a criminal inquiry into the shootings. The State Department’s Bureau of Diplomatic Security gave immunity to all of the Blackwater guards involved in the killings, even though they did not have the authority to do so. The director of the State Department’s Bureau of Diplomatic Security, Richard Griffin, resigned last week. The New York Times reports prosecutors at the Justice Department had no advance knowledge of the immunity deal.