U.S. Customs and Border Protection officers uncovered a female illegal immigrant stuffed inside the wall of a van during a weekend that also netted the agency nearly $5.9 million in narcotics seizures.

CBP officers intercepted more than 1,110 pounds of marijuana, cocaine, methamphetamine, and heroin valued at almost $5.9 million from Friday through Sunday, according to the agency. Over the same period, officers at the San Ysidro port of entry detained 12 illegal immigrants.

The woman found behind a van panel may have been the most surprising. On Friday at about 11:30 p.m., CBP officers encountered a 1993 Dodge Caravan driven by a 43-year-old U.S. citizen and resident of Vista, Calif. During the inspection the CBP officer noted that the driver-side quarter panel felt and sounded unusual when tapped, and referred the vehicle for a more intensive inspection.

CBP officers removed the plastic panel covering the side wall of the vehicle and discovered a woman hiding inside. CBP officers determined that the woman is a Mexican national who was unable to legally enter the United States.

CBP officers paroled the woman into the U.S. to serve as a material witness to the incident before she is returned to Mexico. The driver was booked into the Metropolitan Correctional Center and will face criminal charges. CBP officers seized the vehicle.