San Mateo woman and Fremont man arrested after officers find drugs and illegal firearm during traffic stop with children inside the vehicle

San Mateo, California – Late Friday night, what began as a routine patrol along U.S. Highway 101 quickly escalated into a serious arrest involving drugs, an illegal firearm, and two small children inside a vehicle.

According to the San Mateo PD, at around 11 p.m. on March 13, 2026, members of the Crime Reduction Unit were traveling southbound near the Hillsdale Boulevard exit when their attention was drawn to an SUV drifting repeatedly across lane lines.

The erratic movement raised immediate concerns that the driver might be impaired. Officers followed the vehicle and initiated a traffic stop a short distance away near the intersection of Brittan Avenue and Industrial Road in San Carlos.

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As officers began speaking with the driver, later identified as 35-year-old Laura Aguilar of San Mateo, their investigation quickly took an unexpected turn. While assessing whether Aguilar was under the influence, officers discovered she was in possession of drugs. That discovery prompted a more thorough search of the vehicle.

All occupants were asked to step out of the SUV. Inside were a man and two young children, including one child who had not been secured in a car seat. During the search, officers located additional drugs along with a bullet inside a small bag in the back seat.

The investigation deepened when officers searched a diaper bag that had been within reach of the male passenger. Inside, they found a loaded, unserialized firearm, also known as a “ghost gun.”

The weapon also featured a threaded barrel, which classifies it as an illegal assault weapon under California law. The man was identified as 25-year-old Hector Gonzalez Barajas of Fremont.

Authorities safely released the children to family members at the scene.

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Aguilar and Barajas were both taken into custody and transported to the San Mateo County Jail. Aguilar faces charges including possession of a controlled substance and possessing drugs while armed with a loaded firearm. Barajas faces multiple firearm-related charges, including carrying a concealed weapon in a vehicle and possessing a loaded firearm that was not registered to him.