El Chapo's son has been released by the Mexican military after troops came under fire from suspected cartel members.
Mexican security forces briefly held Ovidio Guzmán López in a house on Thursday but decided to release him to protect lives, Reuters reports.
Chaos broke out in Culiacan as soldiers stormed the area, with fierce gun battles raging in the city's streets.
Ovidio Guzmán López, believed to be in his 20s, is said to have taken a top role in the Sinaloa cartel following his father's capture.
Unconfirmed reports state that another of El Chapo's sons, Iván Archivaldo Guzmán, 39, was also either killed or arrested in the military operation yesterday.
Vice News reports there are rumours Iván Archivaldo Guzmán was killed in a gun battle with Mexican troops.
Joaquin Guzman Loera, commonly known as El Chapo, was the leader of the Sinaloa cartel, a criminal organisation named after the Mexican Pacific coast.
Earlier this year he was jailed for life after being found guilty of trafficking cocaine, heroin and marijuana and engaging in murder conspiracies.
The infamous criminal was transferred to the Colorado's United States Penitentiary Administrative Maximum Facility (ADX) - the only federal supermax prison in the US, in July.
He was put on a police helicopter in New York and flown to an airfield, where a plane was waiting to take him to the prison.
Heavily armed guards and dozens of police officers were involved in the transfer, with the authorities making sure there was no chance for El Chapo to escape justice again.
He will live out the rest of his days alongside terrorists, mobsters and intelligence traitors in the Colorado prison.
