MEXICO CITY (Reuters) - Mexico will not pursue criminal charges against former defense minister Salvador Cienfuegos, the attorney general's office said on Thursday, a decision that raised criticism and comes despite U.S. prosecutors' accusations he collaborated with drug lords.
Cienfuegos, a member of former President Enrique Peña Nieto's government, was arrested in October at Los Angeles international airport and accused by U.S. prosecutors of collaborating with one of Mexico's most powerful drug cartels.
In November, a federal judge granted a U.S. government request to drop drug charges against Cienfuegos and return him to Mexico, which the United States hoped would restore trust in the neighbors' severely strained security ties.
The Mexican attorney general's office said in a statement an analysis of the evidence showed Cienfuegos "never had any encounters with members of the criminal organization investigated by U.S. authorities, nor did he maintain any communication with them, or carry out acts tending to protect or help said individuals."
Mike Vigil, a former U.S. Drug Enforcement Administration chief of international operations, expressed his dismay at the decision.
"This is a very big stain on the Mexican justice system," Vigil said in a television interview with Mexican broadcaster Milenio.
Vigil said Ciefuegos' case would be a model for corruption and impunity in future.
Reuters was not able to contact Ciefuegos.
His arrest in the United States followed a multi-year investigation that used wire taps to track a military figure who traffickers called "El Padrino", or The Godfather.
Investigators concluded "El Padrino" was Cienfuegos and had helped drug traffickers move tonnes of narcotics.
However, the attorney general's office said 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 authorities had decided not to pursue criminal charges against Cienfuegos, a former general, the attorney general's office added.
Some Mexicans saw the decision as another example of long-standing impunity for the military.
"Unfortunately, we see that the army is still untouchable," said Nadin Reyes, whose father went missing in 2007 after last being seen at a military base.