A Kaneohe Bay Marine who died Monday during training in California was hit by a bulldozer, a California-based news website reported.

Pfc. Casey J. Holmes, 20, of Chico, Calif., died during an Integrated Training Exercise at Marine Corps Air Ground Combat Center in Twentynine Palms, Calif.

“Pfc. Holmes was struck by a bulldozer,” Marine Capt. Nicholas C. Mannweiler said, according to the Palm Desert Patch. Mannweiler is based at the combat center.

The Marine Corps said the incident is under investigation.

Holmes enlisted in the Marine Corps in May 2012 and joined the 3rd Battalion, 3rd Marine Regiment at Marine Corps Base Hawaii in October.