A San Joaquin County woman has pleaded guilty to illegal firearms trafficking, acting U.S. Attorney Michele Beckwith said.

Alejandra Susana Castillo, 34, of Tracy, admitted Friday to working with a co-conspirator to traffic firearms they purchased in Nevada and selling them on California’s black market from August 2023 to August 2024.

Last July, Castillo’s unnamed co-conspirator led law enforcement on a chase at speeds over 100 mph, prosecutors said. The pursuit was called off for safety reasons, but two days later, the suspect’s car was seen parked at a gas station. An officer detained Castillo, and a search of the car yielded a semi-automatic rifle in the trunk and three extended magazines.

U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives agents traced more than 30 firearms to the conspiracy, the Department of Justice said. At least three of the firearms have been recovered in connection with suspected firearms-related crimes.

“One such firearm, for example, was recovered in the possession of a felon in Vallejo on July 25, 2024, only three days after Castillo purchased the firearm in Nevada on July 22, 2024,” prosecutors from Beckwith’s office said in a release.

At her scheduled June sentencing, Castillo faces 15 years in prison and a $250,000 fine.

This case is the product of an investigation by the ATF; the California Highway Patrol; the Pleasanton, Tracy and Reno, Nevada, police departments; and the San Joaquin County district attorney’s office, prosecutors said.