‘Semper Infidelis’: Former Marine Pleads Guilty To Smuggling Weapons, Ammunition To Mexican Drug Cartel

An ex-Marine from Whittier, California, pleaded guilty Tuesday to federal charges after leading a smuggling operation that sent weapons and ammunition to a powerful Mexican drug cartel.

Marco Antonio Santillan, 51, and three others were arrested in January as part of “Operation Semper Infidelis” and accused of purchasing guns and ammunition from four different states and smuggling them into Mexico. The weapons were then purchased by the cartel using money made from drug sales, according to prosecutors, the Los Angeles Times reported. 

According to City News Service, Santillan “entered his plea to conspiracy to violate export regulations and conspiracy to commit money laundering, according to the U.S. Attorney’s Office.”

“The indictment stated that Santillan led the gun-trafficking operation that used drug money to purchase assault rifles, hundreds of thousands of rounds of assault-rifle ammunition, and machine gun parts and accessories,” CNS reported. “Some of the items were smuggled into Mexico.”

During their investigation, authorities seized more than 250,000 rounds of ammunition, $300,000 worth of weapons parts, six assault rifles, and kits to fabricate several six-barrel rotary machine guns.

Law enforcement officials said they seized weapons and ammunition that were headed to Mexico, where they would be sold to the Jalisco New Generation Cartel (CJNG). According to the U.S. Drug Enforcement Administration (DEA), CJNG is one of the two most powerful drug trafficking gangs in Mexico, known for sending fentanyl and methamphetamine across the U.S. border through Tijuana, Jaurez, and Nuevo Laredo, the Times noted.  

In 2021, the U.S. saw record-breaking drug overdoses from two of the deadly drugs trafficked by CJNG, according to a report from The New York Times. Synthetic opioids like fentanyl accounted for 71,000 deaths in the U.S., and methamphetamine killed up to 33,000 Americans just last year, according to data from the CDC. 

The FBI charged that Santillan and his co-conspirators smuggled “sophisticated weaponry out of the United States to one of the most violent cartels in Mexico whose members target not only rival gangs, but innocent Mexican citizens and Mexican law enforcement,” Kristi Johnson, assistant director of the FBI’s LA field office, said in a January statement.

City News Service added that Santillan’s 29-year-old son, Marco Santillan Jr., was also charged in the scheme and pleaded guilty last week. 

The former Marine served six months in prison in 1994 after conspiring to import contraband. Santillan is scheduled to be sentenced for his lead role in the weapons smuggling operation on August 8.

“The charge of conspiracy to violate export administration regulations carries a statutory maximum sentence of 20 years in federal prison, while the attempted smuggling counts each carry a maximum penalty of 10 years in prison,” The Department of Justice said in a January press release.