Sixteen Marines at Camp Pendleton have been arrested on charges ranging from migrant smuggling to drug-related offenses.

Here's what we know:

What happened?

The 16 — all junior enlisted Marines whose names have not been released — were arrested Thursday during morning formation. Eight others were detained for questioning in unrelated drug cases.

Why such a dramatic arrest?

“It was a public display for the entire unit to see,” 1st Lt. Cameron Edinburgh, a 1st Marine Division spokesman, told the Union-Tribune.

Why now?

The move comes three weeks after two other Marines were picked up by a Border Control agent in the area and charged with transporting three Mexicans who had illegally crossed into the U.S.

How are the smuggling cases related?

The Marines say the July 3 incident aided in the investigation leading to the arrest of the 16. The Marines have also confirmed that the two Marines were from the same unit as those arrested Thursday, the San Diego Union-Tribune reported.

In the initial case, Lance Cp. Byron Darnell Law and Cpl.David Javier Salazar-Quintero are accused of accepting $1,000 to transport three undocumented migrants from the border area. In court documents, the migrants said they had paid $8,000 to unknown individuals to be smuggled into the U.S.

According to the documents, the two Marines blamed each other for the incident. Law said Salazar had asked if he was interested in making money by picking up an "illegal alien," according to the documents. Salazar, in turn, told authorities that Law introduced him to a man who “recruited” him to help smuggle in migrants.

Are the 16 Marines part of increased border security?

The Marine Corps said in a statement that none of the arrested Marines were among the 6,600 active duty and National Guard troops assigned to strengthen Border Patrol forces along the U.S.-Mexico border.

The Camp Pendleton Marine Base, which is only 55 miles from San Diego's border with Mexico, is cut by Interstate 5 leading to Los Angeles along a well-worn route used by migrant smugglers. More than 42,000 active duty personnel work at the base.

Where are the 16 now?

The marines, who were arrested by division officials and the Naval Criminal Investigative Service, were being held in the brig at Camp Pendleton pending an appearance in federal court.

“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. “Any Marines found to be in connection with these alleged activities will be questioned and handled accordingly with respect to due process.”

Contributing: Associated Press