In this file photo, Secretary of Defense Salvador Cienfuegos Zepeda arrives for a review of the troops that will participate in the Independence Day parade, in Mexico City. (PHOTO / AP)

MEXICO CITY - Mexico will not pursue criminal charges against former defense minister Salvador Cienfuegos, the attorney general’s office said in a statement on Thursday, despite accusations by US prosecutors that he had collaborated with a key drug cartel.

In November, a federal judge granted a US government request to drop drug charges against Cienfuegos and return him to Mexico, which called it a move that would restore trust in the neighbors’ severely strained security ties.

The attorney general’s office said its analysis of the evidence showed Cienfuegos “never had any encounters with members of the criminal organization investigated by US authorities, nor did he maintain any communication with them, or carry out acts tending to protect or help said individuals.”

In November, a federal judge granted a US government request to drop drug charges against Cienfuegos and return him to Mexico, which called it a move that would restore trust in the neighbors’ severely strained security ties

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Cienfuegos, a member of former President Enrique Peña Nieto’s government, was arrested in October at the Los Angeles international airport and accused by US prosecutors of collaborating with one of Mexico’s most powerful drug cartels.

His US arrest followed a multi-year investigation that used wire taps to track a military figure that traffickers had dubbed “El Padrino”, or The Godfather.

Investigators concluded “El Padrino” was Cienfuegos and had helped drug traffickers move tonnes of narcotics.

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However, the attorney general’s office added, there was no evidence Cienfuegos had “used any equipment or electronic means, or that he had issued any order to favor the criminal group identified in this case.”

Scrutiny of Cienfuegos’ wealth and tax obligations uncovered no evidence that he had received illegal income, it said.

These were among the reasons why authorities had decided not to pursue criminal charges against General Salvador Cienfuegos Zepeda, the attorney general’s office added.