Sixteen Marines with 1st Marine Division were arrested on Thursday at a battalion formation for "alleged involvement in various illegal activities ranging from human smuggling to drug-related offenses," the Corps said in a press release.

Another eight Marines were questioned about their involvement in alleged drug offenses, the release said, which added that "information gained from a previous human smuggling investigation precipitated the arrests."

The arrest of the 16 can be traced back to the case of two Marine infantrymen, Lance Cpl. Byron Law and Lance Cpl. David Javier Salazar-Quintero, who were pulled over and arrested by Border Patrol on July 3 — along with three undocumented immigrants in the backseat — as they were allegedly trying to make a quick buck shuttling people from Mexico into the United States, according to a federal court complaint first reported by Quartz.

A source familiar with the matter told Task & Purpose the mass arrest of additional Marines came after the Naval Criminal Investigative Service pulled information from the phones of Law and Salazar-Quintero.

Maj. Kendra Motz, a spokeswoman for 1st Marine Division, told Task & Purpose the unit involved was 1st Battalion, 5th Marine Regiment, the same unit where Law and Salazar-Quintero were assigned. She added that all the Marines arrested or detained were between the ranks of Private First Class and Corporal.

"1st Marine Division is committed to justice and the rule of law, and we will continue to fully cooperate with NCIS on this matter," the release said. "Any Marines found to be in connection with these alleged activities will be questioned and handled accordingly with respect to due process."

The Marines arrested on Thursday were not assigned to the southwest border mission, the release said.

According to the July 3 complaint, Law told Border Patrol that he was an active-duty Marine and dimed out Salazar-Quintero as the organizer of the smuggling operation. "Law stated that last night, Salazar called and asked him if he was willing to make $1000.00 USD picking up an illegal alien," the complaint said.

On July 2nd, Law said they both traveled to Jacumba, California while being guided "via cell phone instructions from an Unknown Mexico number," the complaint said. They then picked up a single immigrant and brought him to a McDonald's parking lot in Del Mar, it continued.

The next day, Law said Salazar called him for another job. This time, they both went to the same area and picked up "three illegal aliens" off the I-8 freeway.

Salazar, meanwhile, said Law introduced him to smuggling through a recruiter. Salazar also admitted to coming to Jacumba to pick up undocumented immigrants on four different occasions, the complaint said.

The three immigrants who were arrested identified Law as the driver of the car that picked them up. Two of them said they were going to pay $8,000 to be smuggled into the U.S.

"We are aware of the charges facing Lance Cpl. Law and Lance Cpl. Salazar-Quintero, and we continue to cooperate fully with the investigative efforts into this matter," Marine spokesman 1st Lt. Cameron Edinburgh previously told Task & Purpose.

This first appeared in Task and Purpose here.