By his early 20s, drug trafficker Horacio Torrecillas Urias Jr. had declared himself the “M30 King of Fresno,” federal authorities say.

On Monday, Torrecillas Urias was officially stripped of his crown. He pled guilty to distributing fentanyl and conspiracy charges involving the intent to distribute methamphetamine and fentanyl, U.S. Attorney Phillip A. Talbert announced in a news release.

Torrecillas Urias, 23, is scheduled to be sentenced by U.S. District Judge Jennifer L. Thurston on Dec. 2. He faces a mandatory minimum sentence of 10 years and a maximum of life in prison. However, the court will determine his sentence after considering applicable statutes and federal sentencing guidelines.

According to court documents, the investigation began after a series of fentanyl pill overdoses in the Fresno area. These overdoses were caused by counterfeit oxycodone M30 tablets containing fentanyl, referred to on the street as M30s.

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All but One Defendant in ‘Operation Killer High’ Has Pled Guilty

The investigation, dubbed “Operation Killer High,” aimed to search for the drug dealers believed to have supplied the toxic pills that caused the spike in fentanyl-related overdoses. The operation uncovered a large drug-trafficking ring led by Torrecillas Urias, the self-proclaimed “M30 king of Fresno.”

Torrecillas Urias was obtaining from sources in Mexico tens of thousands of counterfeit M30 fentanyl pills and large quantities of fentanyl powder, cocaine, and methamphetamine. He and his co-defendants distributed the illegal drugs to dealers inside and outside of California.

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During the investigation, federal, state, and local law enforcement agents conducted traffic stops, intercepted packages, and executed residential search warrants that resulted in the recovery of more than 55,000 counterfeit M30 fentanyl pills, 6 pounds of fentanyl powder, 10 pounds of meth, a pound of cocaine, 25 firearms, and hundreds of rounds of ammunition.

Operation Killer High resulted in charges for 17 other defendants, and all but one has pleaded guilty. The remaining co-defendant, Alma Garza, is set for trial on Sept. 24.

Assistant U.S. Attorney Justin J. Gilio is prosecuting the case.