A Marine was killed Monday, and four others injured, during a training accident on board the Combat Center in Twentynine Palms. About 11:20 a.m. Monday morning, an amphibious-assault vehicle caught fire in the Bullion/Lead Mountain area, killing Corporal Nicholas Sell, 21, and injuring four others. One of the injured is in stable condition at Arrowhead Medical Center; the other three injured Marines were treated and released from the Naval Hospital on board the Twentynine Palms Combat Center. The Marine Corps has not released the names of the other Marines involved. The Marines were supporting 2nd Battalion, 1st Marine Regiment, during the month-long Integrated Training Exercise. Corporal Nicholas Sell, of Eagle Point, Oregon, had deployed to Afghanistan in support of Operation Enduring Freedom and had been in the Marines for three years. The cause of the accident is under investigation. Monday’s incident marks the second training death this year during ITX at the Combat Center. Private First Class Casey Holmes died March 11 in a bulldozer mishap during the training program.