Jesus Alfredo Guzman was arrested early Thursday in Guadalajara for his alleged involvement in smuggling cocaine and heroin into the United States, The Washington Post reported.
Authorities also said they seized several weapons, four grenades, two false identification cards and $135,000 in U.S. currency during Guzman's arrest.
Mexican and U.S. law enforcement agencies worked together to arrest Guzman, who is called Alfredillo by his father. A marine spokesman said the arrest came after months of intelligence work.
"This is a very big blow to Chapo and his closest circle. Alfredillo was a high-ranking member of the cartel, not just some lowly relative who got a job because of his blood ties," Malcolm Beith, author of "The Last Narco: Inside the Hunt for El Chapo, the World's Most-Wanted Drug Lord," told the Post.
"He was doing his dad's business," said a U.S. law enforcement official, who described Guzman as "a bit of a flashy guy but he knew his place."