The Marine Corps has launched a new investigation of an amphibious task force at the center of a disaster at sea last year that killed nine U.S. troops, service officials said, opening the possibility for additional discipline for officers involved.

A board of officers will review the formation of the 15th Marine Expeditionary Unit, of Camp Pendleton, Calif., with Lt. Gen. Carl E. Mundy III serving as board president, the service said in a statement.

“The investigation will inquire into the formation of the 15th MEU; training and material readiness impacting the formation of the 15th MEU; and higher headquarters oversight of the 15th MEU,” the service said. “The goal is to ensure the Marine Corps is doing everything possible to prevent this type of mishap from happening again.”

The new investigation follows an outcry from the relatives of some of the service members killed in the disaster, in which an armored vehicle designed to carry Marines from Navy ships to shore rapidly took on water and sank on July 30 during a training exercise off the coast of California. The families have questioned why no general was held responsible after the initial investigation found numerous failures by Marine officers, including a lack of safety boats, slipshod maintenance, gaps in required training and complacency.

“Why are these men allowed to be in control of people’s lives period anymore? No more. That’s the angry part of me speaking,” Christiana Sweetwood of Danville, Va., whose son was among those killed, said in an interview last week. “Are these generals getting off and these lower-level guys taking the blame?”

Several officers have been removed from their job or disciplined, including Col. Christopher Bronzi, the commanding officer of the 15th MEU, and Lt. Col. Michael Regner, who commanded the 1st Battalion, 4th Marines, a unit of more than 1,000 troops that reported to Bronzi and was a part of his task force.

But investigation’s findings released on March 26 raised the possibility that others also may be culpable. They include Maj. Gen. Robert Castellvi, the former commanding general of the 1st Marine Division, who oversaw the training of the Marines in the platoon of amphibious assault vehicles involved.

Lt. Gen. Steven Rudder, the commanding general of Marine Corps Forces Pacific, found that Castellvi “bears some responsibility” because the Marines involved did not receive a required assessment known as a Marine Corps Combat Readiness Evaluation before they were reassigned to the 15th MEU.

Rudder opted not to discipline Castellvi, noting that the Marines involved already had been transferred under Bronzi. Castellvi is now the service’s inspector general.

The investigation also cited the former commander of the 3rd Assault Amphibian Battalion. The commander, who was not named in the report the service released, failed to make sure that the Marines involved in the AAV platoon received the required combat readiness evaluation and that the vehicles were fully operational before they were assigned to the 15th MEU to prepare for a deployment, the investigation found.

Rudder also wrote in his assessment that the coronavirus pandemic played a role in the disaster.

“In my opinion, this distracted personnel from the attention to detail required to form a MEU,” Rudder wrote. “However, to the extent any such distractions occurred they should not have prevented the units involved from accomplishing their respective missions.”

The disaster prompted a discussion last week between Gen. David H. Berger, the commandant of the Marine Corps, and Adm. Mike Gilday, the chief of naval operations, Gilday said in a call with reporters Monday. The doomed AAV was returning to the USS Somerset, an amphibious ship, following a day of training for the Marines on San Clemente Island, a Navy-owned facility.

“What we discussed was the fact that there are gaps and seams where there shouldn’t be gaps and seams in Navy and Marine Corps operations at the tactical level,” Gilday said. “So these are combined operations that we’ve been doing for some time now, and to have separate requirements on the Marine Corps side and the Navy side just doesn’t make sense.”

The dead were Pfc. Bryan J. Baltierra, 18, of Corona, Calif.; Lance Cpl. Marco A. Barranco, 21, of Montebello, Calif.; Pfc. Evan A. Bath, 19, of Oak Creek, Wis.; Navy Hospitalman Christopher Gnem, 22, of Stockton, Calif.; Pfc. Jack Ryan Ostrovsky, 21, of Bend, Ore.; Lance Cpl. Guillermo S. Perez, 20, of New Braunfels, Tex.; Cpl. Wesley A. Rodd, 23, of Harris, Tex.; Lance Cpl. Chase D. Sweetwood, 18, of Portland, Ore.; and Cpl. Cesar A. Villanueva, 21, of Riverside, Calif.

Seven Marines in the vehicle, including the vehicle commander, survived.