FILE PHOTO: Jun 28, 2025; Anaheim, California, USA; Julio Cesar Chavez Jr. reacts before fighting against Jake Paul at Honda Center. Mandatory Credit: Gary A. Vasquez-Imagn Images/File Photo

MEXICO CITY (Reuters) -Mexican boxer Julio Cesar Chavez Jr has entered a prison in the northern Mexico state of Sonora after his arrest in the United States in July, Mexico's national arrest registry showed on Tuesday.

Mexican President Claudia Sheinbaum in her daily press conference said the 39-year-old been deported. She previously said there was a warrant for his arrest for charges of arms trafficking and organized crime, and that prosecutors were working on the case.

The Mexican attorney general's office declined to comment.

Chavez Jr, the son of a legendary former world champion boxer Julio Cesar Chavez, was detained by U.S. immigration authorities shortly after losing in a sold-out match to American influencer-turned-boxer Jake Paul.

Mexican prosecutors allege he acted as a henchman for the powerful Sinaloa Cartel, which Washington designated a foreign terrorist organization earlier this year.

Chavez Jr's lawyer and family have rejected the accusations.

Mexico's national arrest registry showed that the boxer was arrested at a checkpoint in the Mexican border city of Nogales at 11:53 a.m. local time, and transferred to a federal institution in Sonora's capital of Hermosillo. Chavez Jr was wearing a black hoodie and red sneakers, it said.

Chavez Jr won the WBC middleweight championship in 2011, but lost the title the following year.

His career has been overshadowed by controversies including a suspension after testing positive for a banned substance in 2009, and a fine and suspension after testing positive for marijuana in 2013.

(Reporting by Diego Ore, Raul Cortes and Aida Pelaez-Fernandez; Writing by Daina Beth Solomon; Editing by Sarah Morland)