Mexican authorities have arrested the head of Mexico’s largest drug cartel. Joaquín Guzmán, nicknamed “El Chapo,” was arrested in a condominium building in the resort town of Mazatlán. Guzmán has been imprisoned before, but escaped in 2001, reportedly using a laundry cart. Mexico’s Attorney General Jesús Murillo Karam described how Guzmán was previously able to elude capture.

Jesús Murillo Karam: “This operation over the last month had very definitive moments that led to his arrest. Between the 13th and 17th of February, several homes which he used were discovered, and in some of those homes, which is what complicated the arrest, we discovered that it was connected by several tunnels to seven homes, not only connected by several tunnels, but he always used the city’s drainage system. The doors to the home where he was found were reinforced with lead, and that caused several minutes of delay in opening them, allowing for an escape through the tunnels.”

The United States aided the investigation and will seek Guzmán’s extradition to the United States. Last month, the Mexican newspaper El Universal reported U.S. drug agents had previously held extensive secret negotiations with the Sinaloa cartel, reportedly agreeing not to interfere with its activities or actively to prosecute Chapo Guzmán and other leaders, in exchange for information about rival cartels.