Mexican cartel leader Ismael “El Mayo” Zambada was arrested in Texas for spearheading fentanyl manufacturing and trafficking networks, according to the Department of Justice.

El Mayo is the alleged ringleader of a notorious drug trafficking ring that funnels fentanyl into the United States. His arrest in the Justice Department’s sting operation, alongside fellow gang leader Joaquin Guzman Lopez, comes as the DOJ states that fentanyl is the “deadliest drug threat our country has ever faced.” Fentanyl trafficking into the U.S. surged in 2016, and hundreds of thousands of Americans have died because of the drug over the past five years.