After Joaquín “El Chapo” Guzmán, one of Mexico’s most notorious drug kingpins, was arrested and then transferred to the United States, Mexican authorities had to turn their attention to other high-profile drug traffickers: his sons.

Among them is Ovidio Guzmán López, who has helped lead the powerful Sinaloa drug cartel since his father’s arrest in 2016. Mexican authorities briefly detained the younger Guzmán on Thursday but ultimately released him after his fellow cartel members took to the streets of Culiacan, the capital of Sinaloa state, with military-grade weapons. Footage from the scene showed trucks and a bus on fire and bodies lying in the street.

President Andrés Manuel López Obrador said Friday that security forces released the younger Guzmán to avoid conflict with the cartel, and “to protect the lives of the people.”

A lawyer working for the Guzmán family told the Associated Press that his family said “Ovidio is alive and free."

The gunfight reportedly began when members of Mexico’s security forces were fired on from inside a house in Culiacan, where the Sinaloa cartel maintains a strong presence. They fired back, and found the younger Guzmán inside. But they were ultimately overpowered and released Guzmán to quell fighting on the streets.

Guzmán is in his late 20s, and although he has emerged as an important leader of the cartel, he is not as well known or powerful as two of his brothers, Iván Archivaldo Guzmán and Jesús Alfredo Guzmán, who are nicknamed “los Chapitos,” Spanish for “the little Chapos,” the AP reported.

Their father led the powerful cartel for decades and managed to make two dramatic escapes from prison in Mexico before he was transferred to face trial in the United States. He most recently escaped from Mexican prison in 2015, through an elaborate tunnel system that led to his prison shower. But he was arrested again around six months later, in a complex mission led by Mexican Marines. He is now serving a life sentence at a super-maximum-security prison in Colorado.

The younger Guzmán was also indicted by a U.S. grand jury over charges he and his brother Joaquín Guzmán López were conspiring to traffic and distribute cocaine, methamphetamine and marijuana in the United States. The U.S. Justice Department unsealed the indictment in February, which says Guzmán also goes by the nicknames “El Raton” and “Raton Nuevo,” Spanish for “the mouse” and “new mouse.”

The brother included in that indictment goes by the nicknames “El Güero,” “Güero Moreno” and “El Moreno,” the document said. The term “güero” is Mexican slang for someone with fair hair or complexion. “El Moreno” means “the dark-skinned one.”

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