CULIACÁN, Mexico—The extradition of Joaquín “El Chapo” Guzmán, Mexico’s long-dominant drug lord, has led to an explosion of violence in his home state of Sinaloa, the birthplace of the country’s narcotics industry.

Rival factions are fighting over Mr. Guzmán’s billion-dollar empire as he awaits trial in solitary confinement inside a high-security prison in New York. He was extradited to the U.S. in January on drug-trafficking and murder charges, to which he has pleaded not guilty.

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