FORT WORTH, Texas — An Army captain investigated for allegedly ordering his troops to kill suspected Iraqi insurgents in retaliation for a deadly U.S. base attack will not be prosecuted, Army officials said Friday.

A prosecutor last month said he submitted three pages of possible charges against Capt. Matthew Cunningham, including solicitation of murder and involuntary manslaughter, and was waiting on his superiors to file charges.

But 10 days later, Staff Sgt. Shane Werst, one of Cunningham’s subordinates who shot an Iraqi during a raid, was acquitted of murder.

Lt. Col. Jonathan Withington, a 4th Infantry Division spokesman, said the case against Cunningham “lost prosecutorial merit.” He would have been tried at Fort Hood, Texas, where the 4th Infantry Division is based.