More than a dozen Camp Pendleton-based Marines arrested during a Naval Criminal Investigative Service (NCIS) investigation into allegations of human smuggling have been charged, the U.S. Marines said Friday.

The 13 Marines with the 1st Marine Division face military court proceedings on a range of charges under military law, including general article violations for transporting or conspiring to transport undocumented immigrants. Others include drunkenness, endangerment, larceny and perjury.

The first arrests of the only two named defendants -- Lance Cpl. Byron D. Law and Lance Cpl. David J. Salazar-Quintero -- were made by U.S. Border Patrol agents on July 3, 2019.

On that day, U.S. Border Patrol agents reportedly spotted three undocumented immigrants jump into their car on Interstate 8, just north of the border near Tecate, NBC 7 Investigates first reported after obtaining a federal complaint detailing the alleged activity.

The complaint said the undocumented immigrants told border agents they had agreed to pay the Marines $8,000 to take them north from the border to Los Angeles, eventually intending to head to New Jersey.

A week later, another Marine was arrested in connection with the NCIS investigation.

Then, on July 25, 16 Marines, all E-2 to E-4 in rank, were arrested during battalion formation comprised of about 800 Marines at Camp Pendleton. The following day, investigators confirmed a Navy sailor and two other Marines were also arrested. Several were released.

More than 42,000 active duty personnel work on Marine Corps Base Camp Pendleton.

The base, located on the coast near Oceanside, California, also hosts thousands of Marine reservists for annual training on its firing ranges, Urban Terrain facilities and training areas.