In 1989, the Sinaloa Cartel dug a tunnel between a house in Agua Prieta to a warehouse located in Douglas that it used to smuggle drugs across the international border. It was discovered in May 1990. Following its discovery, the Cartel refocused their smuggling operations towards Tijuana and Otay Mesa, San Diego where it acquired a warehouse in 1992. Other tunnels would also later be built in Arizona including sites at Naco and Nogales.
In 1989, the Sinaloa Cartel dug a tunnel between a house in Agua Prieta to a warehouse located in Douglas that it used to smuggle drugs across the international border. It was discovered in May 1990. Following its discovery, the Cartel refocused their smuggling operations towards Tiju.ana and Otay Mesa, San Diego where it acquired a warehouse in 1992 Other tunnels would also later be built in Arizona including sites at Naco and Nogales.