An attempt to smuggle 13 undocumented immigrants by disguising their vehicle and making them wear U.S. Marine Corps uniforms was foiled by alert U.S. Border Patrol agents with military backgrounds, according to a criminal complaint filed in San Diego last week.

The incident, which made national headlines when it was first reported this week, happened about 10 p.m. Monday last week on Interstate 8 near Boulevard, east of San Diego. Three men have been charged with smuggling in a San Diego federal court.

It's unclear how the smugglers got their hands on the U.S. government license plate on their vehicle and U.S. military uniforms. The Naval Criminal Investigative Service and Border Patrol were conducting a joint investigation of the incident.

The nine-page complaint includes statements from Arturo Leyva Jr., who was identified as the driver of the van, and Jose Guadalupe Ceja, identified as a front seat passenger. Both men were wearing uniforms with the name "Lopez" clearly marked.

Leyva said the license plate was changed in a mobile park in Imperial County and that an "unknown man" provided two large green military-style duffle bags "full of military clothing."

On the night of the arrests, a Campo-based Border Patrol agent, identified only as S. Smith, was on anti-smuggling duty in an unmarked vehicle on I-8 when he spotted two vans with government license plates that appeared unusual, according to the complaint.

The agent zeroed in on one of the vans and noticed that it had a U.S. government license plate that appeared to have been altered.

One of the numbers "did not reflect in his headlights in the same manner as the rest of the numbers," the complaint said.

Agent Smith, who had served in the Army and the Marines, stopped the van and began to doubt the driver was a Marine during questioning. One of the questions he asked was when the Marine Corps celebrates its birthday, which the driver did not know. The U.S. Attorney's Office in its complaint said that the birthday is one of the first things taught to all Marines in basic training.

Another agent, meanwhile, questioned the front seat passenger who could not answer what Marine Corps unit he served in and did not appear to understand English. The occupants in the rear were questioned by another agent and identified themselves as Mexican citizens who did not have permission to be in the Unites States. Some were wearing urban-style uniforms, according to the complaint.

The driver of the van told agents he had been following another vehicle, a green Mitsubishi Eclipse, which was stopped 90 minutes later at a checkpoint in Jacumba. It was there that agents arrested Guadalupe Garcia and found the U.S. Marine insignias.

It's unclear what happened to the first of the two vans agent Smith initially spotted. That van had a Department of Homeland Security license plate.

Leonel.sanchez@sandiegored.com