WASHINGTON — In what appeared to be a new blow to Mexico's Sinaloa Cartel, the imprisoned son of the cartel's co-leader offered a secret guilty plea to narcotics trafficking charges last year and has been cooperating ever since with U.S. agents, prosecutors said Thursday.
The plea deal was made public in Chicago, where Vicente Zambada Niebla, 39, has been imprisoned since his extradition from Mexico in February 2010.
Mr. Zambada is the son of Ismael Zambada, a co-founder of the Sinaloa Cartel, which is based in the state of the same name in northwest Mexico but has tentacles that extend around the world and deeply into the United States.
The elder Mr. Zambada, who remains at large, is thought to have become the cartel's sole leader after the arrest Feb. 22 of Joaquin "El Chapo" Guzman, considered the world's most-wanted drug lord.
A Department of Justice statement didn't make clear why the younger Mr. Zambada's plea deal was kept secret for more than a year, or why it was made public now. Nor did it indicate whether he'd offered information that might have helped lead to Mr. Guzman's arrest in an oceanfront condominium in Mazatlan.
Mr. Zambada's cooperation with U.S. prosecutors comes in the hopes of minimizing a possible life sentence for drug trafficking and a possible fine of $4 million.
U.S. and Mexican agents arrested Mr. Zambada in a five-star Mexico City hotel in 2009. His lawyers later argued that U.S. agents had reneged on an agreement to offer Mr. Zambada immunity in exchange for his providing information about fellow Mexican drug traffickers.
In signing the plea deal, Mr. Zambada admitted to being a "high-level member" of the Sinaloa Cartel from 2005 to 2008 and serving as a "surrogate for his father" in coordinating deliveries of cocaine from Colombia and Panama to Mexico. He also acknowledged facilitating the smuggling of heroin and cocaine to the United States, specifically Chicago.