( CNN ) -- The Marine Corps has dropped charges against the commander of the Marine company involved in the 2005 killings of Iraqi civilians in Haditha , Iraq . Camp Pendleton 's commanding officer ordered charges dropped against Capt . Lucas McConnell . Capt . Lucas McConnell , who had been charged with dereliction of duty , was also granted immunity to ensure he cooperates with the investigation , the service said Tuesday . McConnell was one of four officers charged with failing to properly investigate and report the civilian deaths . Lt. Gen. James Mattis , the Marine commander in charge of the corps ' units in the Middle East , ordered the charges dismissed last week . `` Lt. Gen. Mattis determined that administrative measures are the appropriate response for any errors or omissions allegedly committed by McConnell , '' according to a statement from the Marine Corps base at Camp Pendleton in California . Four Marines from McConnell 's unit were charged with murder in connection with the deaths of up to two dozen civilians in Haditha in November 2005 . Charges have been dropped against two of them -- one in exchange for his testimony and the other after a hearing officer decided he acted in accord with the rules of engagement . Two other officers -- Lt. Col. Jeffrey Chessani , the battalion commander , and 1st Lt. Andrew Grayson -- also face charges related to their response to the killings . Haditha , located along the Euphrates River northwest of Baghdad , was the target of several Marine campaigns aimed at rooting out insurgents from 2004 through 2006 . Prosecutors accused the Marines of going on a rampage after a roadside bomb killed one of their comrades , 20-year-old Lance Cpl . Miguel Terrazas , on November 19 , 2005 . A statement from the Marine Corps originally blamed the deaths on the roadside bomb , triggering a parallel investigation into how commanders handled the incident . E-mail to a friend .
Lt . John McConnell was accused of poor investigating , reporting of deaths . Two other officers face charges due to their contribution to the killings . They killed up to two dozen civilians in Haditha , Iraq , in April 2005 .