A dozen Marines are currently confined to the Camp Pendleton, California, brig for their alleged involvement in human smuggling and drug offenses, according to Marine officials.

Charges against the 12 Marines, all from 1st Battalion, 5th Marines, are still pending, according to the 1st Marine Division.

Two of the 12 Marines being held at the Pendleton base brig, Lance Cpl. Byron Darnell Law II and Lance Cpl. David Javier Salazar-Quintero, were arrested by Border Patrol agents on July 3 for their alleged involvement in smuggling three undocumented immigrants near the U.S.-Mexico border for financial gain.

The other 10 Marines confined to the Camp Pendleton brig were arrested by Naval Criminal Investigative Service during a battalion formation on July 25 for allegations related to human smuggling and drug offenses.

“Each case and alleged level of participation varies among the individual Marines and Sailor,” the 1st Marine Division said in a release. “All personnel involved are presumed innocent until proven guilty.”

The battalion formation mass arrest on July 25 carried out by NCIS originally nabbed 16 Marines. NCIS later announced it had arrested two other Marines assigned to 1/5 and a Navy corpsman.

In total, 18 Marines and a Navy corpsman were arrested on July 25 for allegations related to drugs and human smuggling.

Marine officials said the NCIS mass arrest stemmed from information learned from another investigation.

The other Marines from 1/5 who were questioned or detained during NCIS’ mass arrest have since been released back to their commands.

Investigations into the smuggling allegations are still underway, the 1st Marine Division said.