Eighteen Marines and one sailor from Camp Pendleton, California, have been arrested after investigators with the Naval Criminal Investigative Service (NCIS) linked the group to crimes related to human trafficking and drug use. According to a report from Newsweek, the 19 service members are all assigned to the 1st Battalion, 5th Marine Regiment.

“NCIS apprehended 18 Marines and one sailor yesterday in relation to an ongoing investigation into allegations of human smuggling and drug-related offenses,” wrote Jeff Houston, NCIS Public Affairs, in an email to Newsweek. “The 1st Marine Division is cooperating with NCIS on this matter.”

Of the 18 arrested, at least eight were suspected of drug offenses; the others are presumed to be involved in some level of human trafficking, although the USMC has not released their names. In a statement to Newsweek, public affairs staff from the 1st Marine Division stated the arrested Marines and one Navy corpsman have not been formally charged with a crime.

These latest arrests seem to be tied to another incident that occurred on July 3. According to USA Today, Lance Corporal Byron Darnell Law and Corporal David Javier Salazar-Quintero were apprehended by U.S. Border Patrol agents while attempting to smuggle three non-U.S. citizens into the country near Jacumba Hot Springs in San Diego County, California. The two Marines arrested in early July each blamed the other, although they did admit they were recruited by a third person. It is unknown if the person who recruited Law and Quintero is a fellow service member.

The Marines who were arrested are currently being held at Camp Pendleton. The USMC has vowed to dispense appropriate justice if the suspects are indicted.

“1st Marine Division is committed to justice and the rule of law, and we will continue to fully cooperate with NCIS on this matter,” military officials said in a statement, according to USA Today. “Any Marines found to be in connection with these alleged activities will be questioned and handled accordingly with respect to due process.”