SAN CLEMENTE ISLAND (CNS) - Authorities Monday publicly identified one Marine who was killed and eight other service members presumed dead after an amphibious assault vehicle sank during a training mission last week near San Clemente Island.

What You Need To Know

  • Authorities publicly identified Marine who was killed and eight others missing and presumed dead

  • Troops were aboard an amphibious assault vehicle that sank during a training mission last week

  • 15 Marines, one Navy sailor were onboard when the vehicle began taking on water

  • 26-ton amphibious vehicle went down 1,000+ yards from a beach on northwest side of  San Clemente Island

Lance Cpl. Guillermo S. Perez, 20, of New Braunfels, Texas, was pronounced dead at the scene of the training accident, which occurred around 5:45 p.m. Thursday roughly 70 miles off the coast of San Diego, according to Marine officials. Perez was a rifleman with Bravo Company, Battalion Landing Team (BLT) 1/4, 15th Marine Expeditionary Unit.

The eight service members presumed dead are:

Pfc. Bryan J. Baltierra, 19, of Corona in Riverside County, a rifleman with Bravo Company, BLT 1/4, 15th MEU.

Lance Cpl. Marco A. Barranco, 21, of Montebello, California, a rifleman with Bravo Company, BLT 1/4, 15th MEU.

Pfc. Evan A. Bath, 19, of Oak Creek, Wisconsin, a rifleman with Bravo Company, BLT 1/4, 15th MEU.

U.S. Navy Hospitalman Christopher Gnem, 22, of Stockton, California, a hospital corpsman with Bravo Company, BLT 1/4, 15th MEU.

Pfc. Jack Ryan Ostrovsky, 21, of Bend, Oregon, a rifleman with Bravo Company, BLT 1/4, 15th MEU.

Cpl. Wesley A. Rodd, 23, of Harris, Texas, a rifleman with Bravo Company, BLT 1/4, 15th MEU.

Lance Cpl. Chase D. Sweetwood, 19, of Portland, Oregon, a rifleman with Bravo Company, BLT 1/4, 15th MEU.

Cpl. Cesar A. Villanueva, 21, of Riverside, a rifleman with Bravo Company, BLT 1/4, 15th MEU.

Fifteen Marines and one Navy sailor were inside the land and sea-going vehicle en route to a waiting ship when it started taking on water, said Lt. Gen. Joseph Osterman, commanding general of 1st MEF.

Seven of the personnel were able to get out of the sinking vehicle and were pulled from the water. Medics took two of them to Scripps Memorial Hospital La Jolla, where both were admitted in critical condition.

One of them was upgraded to stable condition as of Sunday night, Marine officials said.

The other five rescued Marines received clean bills of health and returned to their units, officials said.

The 15th MEU, 1st Marine Expeditionary Force (MEF), and the Makin Island Amphibious Ready Group (ARG) had been working together to try to locate more survivors, but they concluded the search and rescue operation Saturday after 40 hours of searching across 1,324 square miles.

The 26-ton amphibious vehicle went down more than 1,000 yards from a beach on the northwest side of the San Clemente Island in water several hundred feet deep, Osterman said.

"It's really below the depth that a diver can go to," Osterman told reporters.

The incident will be the subject of an exhaustive investigation, according to USMC officials.

"Our thoughts and prayers have been, and will continue to be with our Marines' and sailor's families during this difficult time," said Col. Christopher Bronzi, the commanding officer of the 15th Marine Expeditionary Unit (MEU). "The steadfast dedication of the Marines, sailors, and Coast Guardsmen to the persistent rescue effort was tremendous."

All of the Marines involved were assigned to the 15th Marine Expeditionary Unit, based in Camp Pendleton.

The Undersea Rescue Command will now deploy an underwater drone to look for remains on the ocean floor, with support from offshore supply ship HOS Dominator.

San Clemente Island is one of the eight islands that make up the Channel Islands archipelago.

The island is owned and operated by the U.S. Navy and is part of Los Angeles County. It is administered by Naval Base Coronado.