Revelations Stir Up Colosio Probe : Mexico: New ‘evidence’ revives theory that slain presidential candidate was victim of government plot.

TIJUANA â€”  The unsolved assassination of Mexican presidential candidate Luis Donaldo Colosio has become a labyrinth of intrigue and suspicion in which solid evidence remains painfully scarce.

Therefore, recent revelations--a letter written by Mexico’s president and comments by the governor of Baja--have set off a furor among journalists and politicians, the social forces driving the case in the absence of progress by investigators.

Although the new “evidence� is circumstantial and ambiguous, it has generated political combat and revived accusations that Colosio fell victim to a high-level government plot.

Repercussions continued this week from a bombshell published by the Reforma newspaper: a letter to Colosio written by President Ernesto Zedillo, then the manager of the Colosio campaign, four days before last year’s assassination.

The letter urged Colosio to mend an apparent rift with then-President Carlos Salinas de Gortari, offering a compelling clue to those who believe that the murder resulted from internal political conflict.

“The letter is of utmost importance to solve the assassination . . . because it establishes with clarity that there were serious differences between Salinas and his candidate,� said commentator Heberto Castillo in Proceso magazine, joining a chorus of pundits, politicians and corruption-weary voters demanding that Salinas be investigated.

The fallout has deepened the woes of Mexico’s ruling Institutional Revolutionary Party, or PRI, according to Gov. Ernesto Ruffo Appel of Baja California, who belongs to the opposition National Action Party, or PAN.

“The disputes among the leaders of the ruling party, many of them in the federal government, are getting bitter,� he said. “And probably there will be a showdown soon, and this could suddenly result in a crisis of state.�

The acrimony about the Colosio case will persist as long as investigators fail to identify a mastermind, thereby ceding the initiative to a relentless press corps, analysts say.

A judge convicted the first accused assassin, Mario Aburto Martinez, of shooting Colosio point-blank after a speech in Tijuana. In February, police arrested an alleged second gunman and accused campaign bodyguards of a cover-up.

Expectations raised by those spectacular charges have faded.

Little additional proof has emerged against Othon Cortez Vasquez, a ruling party aide and security guard accused of firing the second shot.

Authorities have not explained who commanded the gunmen; speculation focuses on politicians and drug lords.

Opinion polls and accusatory articles and books suggest that many Mexicans suspect Salinas, the former president, who has denied the accusations. Critics allege that Salinas grew angry at Colosio for asserting independence and promising reform.

To some, the letter from Zedillo dated March 19, 1994, confirms that reputed estrangement.

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Acknowledging the uncertain state of the campaign, Zedillo recommends that Colosio establish “a political alliance with [the] President. You must offer him all your loyalty and support so that he can conclude his mandate with great dignity.�

The letter advises the candidate against criticizing the government without prior approval.

In Mexico’s rigidly hierarchical presidential politics, analysts say, such advice reflects extraordinary tension.

The Tijuana weekly Zeta asked: “How is it possible that Luis Donaldo Colosio could not approach and speak in confidence with Carlos Salinas de Gortari after this president chose him as candidate?�

Colosio’s campaign had run into trouble, chiefly the high-profile rivalry of Manuel Camacho Solis, the former mayor of Mexico City. Camacho Solis waged a shadow-candidacy that the president appeared to tolerate, if not encourage, feeding rumors that Colosio would be replaced.

Indeed, Zedillo’s letter describes Camacho Solis as cultivating the “new priorities� of Salinas with the possible goal of “substitution of the candidate.�

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Ultimately, Zedillo replaced the slain Colosio. Zedillo has criticized the newspaper for revealing a “strictly personal� correspondence.

The aftermath has also featured angry words between government figures and the maverick Camacho Solis. This apparently hastened a long-awaited move: Camacho Solis resigned from the PRI. He submitted a 10-page declaration to the attorney general about events surrounding the assassination, officials said this week.

Meanwhile, a charismatic legislator who organized the rally where Colosio was shot has denied any link to activists who were arrested after the assassination with hand-painted signs protesting the killing.

The signs were allegedly painted before the slaying, Ruffo revealed, saying the activists worked for Congressman Jaime Martinez Veloz. Martinez accused Ruffo of taking political revenge on him.