Marine Sergeant Major Fired from Recruit Depot Was Arrested and Faces NCIS Investigation

A senior enlisted Marine at the service's West Coast recruit depot is in pretrial confinement and under investigation by law enforcement after being fired Thursday for "loss of trust and confidence."

Sgt. Maj. Gerardo Trevino, the senior enlisted leader in charge of 3rd Recruit Training Battalion at Marine Corps Recruit Depot San Diego , was relieved of his duties last week by Col. Peter Rummler, the commanding officer of the depot's recruit training regiment, the Marine Corps said in a statement to Military.com over the weekend.

The Naval Criminal Investigative Service, or NCIS, confirmed Monday that Trevino is in pretrial confinement and said it is conducting an investigation into the case. The battalion Trevino helped lead is responsible for molding recruits through basic training into Marines.

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"NCIS is conducting an investigation, and no further details will be released at this time," Capt. Austin Gallegos, a spokesperson for the recruit depot, told Military.com after confirming that Trevino had been relieved last week.

While Gallegos would not provide details as to what the Navy 's law enforcement agency is probing in relation to Trevino, NCIS is primarily responsible for investigating crimes, as well as preventing terrorism and safeguarding secrets for the Navy and Marine Corps, according to its website.

Trevino's firing follows seven known reliefs or reassignments of leaders responsible for Marine training in the last 14 months. Last year, a senior enlisted leader at Quantico 's Basic School was fired after she struck two pedestrians in an alleged drunk-driving case.

By last July, three top leaders at the Marine Corps' East Coast recruit depot at Parris Island were relieved from their positions. Three leaders at the School of Infantry-West, located aboard Camp Pendleton , California, and responsible for training infantry Marines after boot camp, were also relieved for "loss of trust and confidence."

"Loss of trust and confidence" is a catchall term the services use to explain -- often with few details -- why a leader was fired.

Trevino joined the Marine Corps in 2004, meaning that he was likely months away from the 20-year mark that most senior service members retire at. He deployed three times, including to Afghanistan and Iraq, according to his official biography, which later appeared to have been scrubbed from the Marine Corps' official site. He was promoted to sergeant major in June 2023 and received orders to the battalion from which he was fired.

As a staff sergeant, "Trevino was awarded the Dan [Daly] Award for being the most inspiration[al] Drill Instructor of India Company and was also promoted to the rank of gunnery sergeant [in] March 2016," his biography said.

Military.com attempted to reach Trevino through publicly listed contacts as well as by email, but was unsuccessful.

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