Maj. Gen. William Mullen, a retired Marine general who served as the commanding general of the Marine Corps Air Ground Combat Center at Twentynine Palms, was found dead at the base over the weekend. The Naval Criminal Investigative Service (NCIS) is conducting an investigation into his death, which occurred under non-combat, medically unattended circumstances. Mullen had a distinguished 34-year career, which included deployments in Iraq and Yugoslavia, and served as a Marine aide to President Bill Clinton. The San Bernardino County Coroner's office is performing an autopsy to determine the cause of death amid a severe heat wave in the region. NCIS has not provided further details, citing the ongoing investigation. Mullen retired in 2020 after his last assignment as the commanding general of the Marine Corps Training and Education Command.