Vicente Zambada Niebla. EFE

A high-level member of Mexico’s Sinaloa drug cartel, who was captured last year, is cooperating with US law enforcement authorities, the Justice Department announced on Thursday.

Vicente Zambada Niebla, who is known as “El Vicentillo” and is the son of the cartel’s current leader, Ismael “El Mayor” Zambada García, pleaded guilty to drug trafficking charges in the US District Court in Chicago earlier this month.

Thirty-nine-year-old Zambada Niebla was arrested by the army in May 2009 in Mexico City, and was extradited to the United States 11 months later to face drug charges stemming from a grand jury indictment handed down in Chicago.

Because of his plea bargain and depending on the level of his cooperation, the US Justice Department said Zambada Niebla would avoid trial and could receive a reduced sentence. He is currently facing a mandatory sentence of life in prison and a minimum of 10 years.

His father took over the Sinaloa Cartel following the capture last February of its notorious leader, Joaquín “El Chapo” Guzmán.

According to a US Justice Department press release, Zambada Niebla admitted that he was a high-level member of the cartel and acted “as a trusted lieutenant” to his father.

“Zambada Niebla admitted he was aware that his father had been among the leaders of the Sinaloa Cartel since the 1970s and that their principal livelihood was derived from their sale of narcotics in the United States,” the release said.

“The plea agreement goes against the spirit of the extradition treaty, especially in this case”

The announcement by Washington surprised Mexican authorities. “The plea agreement goes against the spirit of the extradition treaty, especially in this case,” Mexican judicial sources told EL PAÍS. “This raises suspicions about the real purpose of the plea agreement since Zambada had already said that he had a similar pact with the DEA that we were never able to determine whether was true or not.”

Follwing his arrest in Mexico City, various Mexican news outlets reported that Zambada Niebla had met with members of the US Drug Enforcement Administration (DEA) and embassy officials at the Sheraton Hotel in the capital. He was promised immunity from prosecution in exchange for providing information on the Sinaloa and other rival cartels, the media reported.

His lawyers in the United States have based their defense on this prior agreement. The trial had been postponed on several occasions following a barrage of secret filings between the defense and the US Attorney’s Office in Chicago.

Among his co-defendants are his father and “El Chapo,” who still remains in Mexican custody. The United States has said it is interested in bringing Guzmán to face charges in a US court. Zambada García is believed to be somewhere in Mexico.