1st Lt. Oliver David, a spokesman at Camp Lejeune in North Carolina, said in a press release Wednesday that a Marine operating a 60 mm mortar tube and ammunition "did not follow correct procedures, resulting in the detonation of a high explosive round at the mortar position."
The investigation initiated by Brig. Gen. James Lukeman, the commanding general of the Camp Lejeune-based 2nd Marine Division, also determined that the mortar team involved in the accident had not conducted "appropriate preparatory training" leading up to the nighttime live-fire exercise.
The Marines did not release a copy of the investigative report and declined to provide any further details about the nature of the deadly mistake. Officials also would not say whether changes to training procedures were enacted as a result of the review.
Marine officials announced earlier this month that two officers and a non-commissioned officer were removed from command following the March 18 accident at Hawthorne Army Depot. Seven Marines and a sailor were also wounded.
Lukeman relieved battalion commander Lt. Col. Andrew McNulty on May 8. Company commander Capt. Kelby Breivogel and Chief Warrant Officer 3 Douglas Derring, the battalion's infantry weapons officer, were also relieved of their duties.
According to the release, Lukeman relieved the officers because "he lost trust and confidence in their ability to ensure proper preparation for, and conduct of, live-fire training events."
David said no criminal charges are anticipated as a result of the investigation.
The investigation also determined that the 60 mm mortar functioned properly and that the weapon system is safe when used as designed by properly trained Marines. The mortars are back in use after training on them was suspended following the accident, officials said.
The Marines killed ranged in age from 19 to 26. All were based at Camp Lejeune.
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