The officers were conducting outbound enforcement operations at the bridge when they encountered a green Ford SUV driving southbound to Mexico. A CBP officer referred the vehicle for further inspection. 

CHICAGO CBP OFFICERS STOP THOUSANDS IN FAKE BILLS AND COUNTERFEIT MERCHANDISE AT O’HARE

After a physical inspection of the vehicle, officers discovered 1,200 .308-caliber rifle rounds and 1,000 .223-caliber rifle rounds concealed within the vehicle. 

CBP OFO seized the ammunition, and special agents with Homeland Security Investigations (HSI) special agents arrested the driver, a 33-year-old U.S. Citizen. 

"The undeclared exportation of weapons and ammunition into Mexico is illegal," Port Director Carlos Rodriguez said in a statement. "Our CBP officers prevented these bullets from reaching Mexico thanks to their diligent inspection work."