Seventeen people were arrested in Southern California on charges of smuggling large quantities of cocaine, heroin and methamphetamines into the United States from Mexico.

Authorities raided more than a dozen different locations in the region.

“This investigation has dealt a serious blow to a trafficking network we believe was funneling significant quantities of high-grade methamphetamine, cocaine and heroin into the Los Angeles area,” Claude Arnold, special agent in charge of U.S. Immigration and Custom Enforcement’s Homeland Security Investigations in Los Angeles, said in a statement.