In sweeping indictments, the Justice Department targeted two dozen operatives in the Chapitos network of the Sinaloa cartel. But many drug policy experts say this won't slow fentanyl deaths.

Their companions are recovering in a U.S. hospital. So far, only one arrest has been made in relation to the kidnapping.

The State Department said the victims, who were found alive after days in captivity, are back on U.S. soil. Officials said they are in the process of returning the remains of two others to the U.S.

Cartels are increasingly turning to huge, industrial-scale labs to churn out synthetic drugs as they shift away from naturally grown drugs like opium and marijuana.