A suspected top assassin in Mexico’s Sinaloa drug cartel was extradited Saturday to the United States, where he will face charges linked to drug and weapons smuggling, the Justice Department announced.

Nestor Isidro Perez Salas, known as “El Nini,” was one of the Sinaloa Cartel’s “lead sicarios, or assassins, and was responsible for the murder, torture and kidnapping of rivals and witnesses who threatened the cartel’s criminal drug trafficking enterprise,” Attorney General Merrick Garland said in a statement after the extradition Saturday morning.

“We also allege El Nini was a part of the Sinaloa Cartel’s production and sale of fentanyl, including in the United States,” Garland said.

The U.S. had offered up to $3 million for information leading to the arrest of Perez Salas, who faces charges of conspiracy to traffic fentanyl, cocaine and weapons, among others.

He is thought to be a close associate of the sons of Mexican drug lord Joaquin “El Chapo” Guzman, who is serving a life sentence in the U.S.

He was arrested in the northwest Mexican city of Culiacan in November 2023, less than a week after President Biden and Mexican President Andres Manuel Lopez Obrador pledged to coordinate more closely on fighting drug trafficking, especially that of the powerful synthetic drug fentanyl.

“El Nini played a prominent role in the notorious Sinaloa Cartel, one of the deadliest drug trafficking enterprises in the world,” Mr. Biden said in a statement Saturday. “The United States has charged him for his role in illicit fentanyl trafficking and for murdering, torturing, and kidnapping numerous rivals, witnesses, and others. This is a good day for justice.”

At the time of his arrest, Mike Vigil, former head of international operations for the U.S. Drug Enforcement Administration, described Perez Salas to the Associated Press as “a complete psychopath,” adding that “taking him out of commission is a good thing for Mexico.”  

The U.S. saw more than 107,000 drug overdose deaths in 2023, according to the Centers for Disease Control and Prevention. Fentanyl accounted for about 70 percent of them.

The U.S. government says fentanyl is often made from products sourced in China, and then is smuggled across the border from Mexico by drug traffickers, especially the Sinaloa cartel.