Ricardo Monreal

Sen. Ricardo Monreal of Zacatecas state, seen here in 2006, said he must step aside until an investigation is completed. (Gregory Bull / Associated Press / July 9, 2006)

The Mexican senator at the center of an ugly drug scandal temporarily stepped down Wednesday, saying he welcomed an investigation he expects will clear his name.

Coming six weeks before national midterm elections, the allegations involving 14 1/2 tons of marijuana found on property belonging to the senator's family have inflamed suspicions widely held by Mexicans that many politicians are in cahoots with powerful drug traffickers.

Sen. Ricardo Monreal of Zacatecas state has acknowledged that the property where the pot was found, in a pepper-drying warehouse, belongs to one of his brothers. But he claims the drug was planted by political rivals.

Monreal is a former governor of Zacatecas, and another brother, David, is mayor of the city, Fresnillo, where the warehouse is located and is a likely candidate in separate elections for the governorship next year.

Mexican Interior Minister Fernando Gomez Mont confirmed that the Monreal property was under investigation after the Jan. 22 raid. With that, a rare public acknowledgment of an ongoing investigation, Sen. Monreal said he had to step aside for a three-week period while the probe runs its course.

"I cannot remain quiet, nor permit that the men and women of Mexico think all of us politicians are alike," Monreal said. "That we all hide behind constitutional protection to avail ourselves of impunity and corruption. I will not form part of that mafia."

That is, in fact, exactly what many Mexicans think of their political elite. Despite years of rumors and allegations that a number of senior political figures have colluded with or been paid off by traffickers, few, if any, are ever prosecuted or jailed, and in fact they often continue unimpeded in their political careers.

"At the least, the senator is covering up. When will our people learn to deny the vote to those who don't deserve it?" read a letter to the editor in the Reforma newspaper. The writer added that Mexican society was "hurt and offended" by what he called cynical and criminal behavior.

It's not the first time Monreal has been dogged by such allegations. In the late 1990s, rumors that his brothers were mixed up with traffickers cost him his party's candidacy for the Zacatecas governorship. He quit the Institutional Revolutionary Party, or PRI, jumped to another party and won the election anyway.

The taint of drug trafficking has touched nearly every political party in Mexico. The PRI's national president, Beatriz Paredes, was quoted Wednesday as saying she had submitted the names of several candidates to authorities for vetting because of suspicions about them in some quarters. They included the PRI's candidate for the governorship of Colima, Mario Anguiano, whose brother is in jail on drug charges, Paredes told Reforma. All were cleared, she added.

On July 5, Mexicans will vote nationwide for a new Chamber of Deputies, the 500-member lower house of Congress, and in six states for governor.

Monreal's difficulties now are also part of a political feud between his family and that of Gov. Amalia Garcia, ultimately over control of Zacatecas and the lucrative business that goes with it, analysts say.

Monreal and Garcia have been trading insults and accusations after people in her government circulated a video highlighting the raid on the Monreal property. Monreal retaliated and said last weekend's prison break in Zacatecas, in which 53 narco hit men and others escaped, shows that Garcia's government is working with criminal syndicates.

He went on to suggest that Garcia's allies had planted the marijuana on his brother's farm as part of a "dirty war" against the family.

Garcia, who has acknowledged that the prison break was an inside job and has arrested or fired dozens of prison officials, shot back that Monreal was a "coward" grasping for more power.

As it happens, two of the escapees, Reynaldo Piña Resendez and Jorge Cervantes Rodriguez, are alleged gunmen with the Gulf cartel captured in the raid that netted the marijuana on the Monreal property.

wilkinson@latimes.com