U.S. Custom and Border Patrol agents credit a routine screening for a big drug bust.
The alleged discovery of meth and cocaine came at SFO after two men flew in from Mexico in late December.
Officers said they found false sides inside the passengers' suitcases that held some 20 pounds of methamphetamine and cocaine. They said an x-ray showed "anomalies" and they tipped officers to do a more thorough inspection of the suitcases.
CBP officers identified the two passengers as Pedro Daniel Rodriguez, 21, and Yuniba Elizabeth Cordero, 22. Both are U.S. citizens.
Investigators said the drugs had a street value of more than $500,000.
The pair were turned over to U.S. Immigration and Customs Enforcement and Homeland Security Investigations agents.
U.S. Customs said in addition to narcotics interdiction, CBP routinely conducts random inspection operations on arriving and departing international flights and intercepts currency, weapons, prohibited agriculture products or other illicit items.
