MEXICO CITY—The reported discovery in cartel hands of a sheaf of police documents containing agents' names and contact numbers, along with apparent references to shared U.S. intelligence data, has renewed fears of high-level corruption in Mexico's war on drugs.
The trove of papers -- which also included an apparent drug cartel payroll listing police commanders -- was found in the car of an associate of Mexico's most powerful drug lord, Joaquin "El Chapo" Guzman, during a May 2009 bust, the newspaper Reforma said Monday.
The papers appeared to be internal documents, possibly memos or registers, from Mexico's federal Public Safety Department and were listed as evidence of criminal charges, copies of which were obtained by Reforma.
The newspaper did not say how it obtained the documents, and the spokesman for the Attorney General's Office, Ricardo Najera, said he could neither confirm nor deny their authenticity. The Public Safety Department did not immediately respond to requests for comment.
The list reportedly included the names and postings of federal police officials. One annotation, apparently made by traffickers, describes some investigations said to originate from the U.S. Drug Enforcement Administration.
Coming less than two years after a widespread corruption probe known as "Operation Clean House" toppled Mexico's former anti-drug czar -- Noe Ramirez -- and other top officials for allegedly collaborating with a drug cartel, the revelation raised questions about whether Mexican law enforcement has really been cleaned up.
"Operation Clean House was a warning that something wasn't working, and this confirms that it still isn't working," said Jorge Chabat, a Mexican expert on drug cartels.
The documents would have let traffickers know which police officials were posted to key trafficking routes, and could have allowed criminals to contact or threaten the agents. One annotation in a pay book written in what appears to be code mentions soldiers and police who purportedly got payments; one is listed with the letters "PFP," an apparent reference to federal police.
"What I see clearly here ... is that the process of infiltration continues" among Mexican police, said Samuel Gonzalez, the country's former top anti-drug prosecutor.
Referring to President Felipe Calderon's goal of having police forces cleaned up by the time his term ends, Gonzalez said, "How are they going to clean up the force by 2012, if they continue to have this infiltration?"
Guzman's Sinaloa cartel has reportedly been gaining ascendancy in the world of Mexican drug trafficking in recent months. The leadership of the rival Beltran Leyva cartel, which had long run one of the most effective smuggling networks, has been hit hard by a Mexican government offensive that recently claimed the lives or liberty of its top leaders.
U.S. law enforcement authorities told The Associated Press last month that Guzman had largely won the battle for the lucrative and hotly contested trafficking route through the violent border city of Ciudad Juarez, across from El Paso, Texas.
Allegations have long circulated that Public Safety Secretary Genaro Garcia Luna, who emerged as the top law enforcement officer after Operation Clean House, may have somehow favored the Sinaloa cartel headed by Guzman.
Garcia Luna has denied any link to the Sinaloa cartel, and Calderon has said the department has fought all the cartels equally.
No firm proof of favoritism has ever been presented, but the arrests of top drug capos have hit all of Mexico's other cartels, while leaving Sinaloa's leadership largely untouched.
The references to U.S. intelligence documents in the documents, if confirmed, could endanger U.S.-Mexico anti-drug cooperation, Gonzalez said.
But, he added, "I don't think they (officials on both sides) have the luxury of allowing it to collapse completely."
Garcia Luna has proved a valuable ally to the United States, noted David Shirk, director of the University of San Diego's Transborder Institute, so much so that "there is a certain degree of real concern in the (U.S.) administration" that Garcia Luna will leave office with Calderon in 2012.
Unless more compelling evidence emerges than just some leaked documents, the Americans are likely to continue working with him, Shirk said.
"The DEA has to look at this and say, well, who's getting us results?" he said.
"When you're dealing with systemic corruption, you sort of have to presume innocence with caution," Shirk added. "You know there are people out there who are not innocent, but you have to work with somebody, as best you can. You take whatever countermeasures you can."
More than 22,700 people have been killed in drug violence since Calderon launched his anti-cartel offensive open taking office in December 2006.
Police in the border city of Tijuana said Monday that they were investigating several weekend murders after finding three charred bodies, while authorities in Zacatecas were investigating an attack on police headquarters that killed one officer and injured another.