MEXICO : Savvy New Top Lawman Doesn’t Fit the Mold : Antonio Lozano, named attorney general, is quiet and studious. As an opposition-party Cabinet member, he breaks a 65-year tradition.

At first glance, there’s little in Antonio Lozano’s personality that would qualify him to be Mexico’s answer to flamboyant crime-buster Eliot Ness: Lozano is bland. He’s quiet. He’s studious. He has insisted, so far, that he will conduct no interviews.

“He’s punctual, efficient and responsible,” opposition leader Carlos Castillo Peraza said of the man now charged with ridding Mexico of its notoriously corrupt judges and police, breaking the nexus here of drug dealers and politicians and solving this year’s two political assassinations that rocked the country to its core.

But look again at the man who already broke 65 years of Mexican tradition last week when President Ernesto Zedillo appointed him Mexico’s attorney general.

At 41, Mexico’s new top law enforcement official--the first member of an opposition party to serve in the Cabinet since the first Institutional Revolutionary Party president took office in 1929--is considered one of the nation’s brightest young criminal lawyers.

Lozano knows politics and politicians.

He served four years in the Chamber of Deputies after he was elected from Mexico City in 1988. That same year, he co-hosted a radio show called “Armed With the Law” with his trusted law partner and National Action Party (PAN) colleague, Hiram Escudero, whom Lozano appointed deputy attorney general Monday.

Unlike most of his Cabinet colleagues, Lozano is neither rich nor privileged. He attended public schools. His law degree is from the Autonomous National University of Mexico, one of the world’s largest, least expensive schools.

But like Chicago’s legend, who went after Al Capone and established a new rule of law in the 1920s, Lozano pulls no punches.

Clearly, there is a new lawman in town.

“This is an institution mired in a profound credibility crisis,” Lozano declared of his powerful office the day he inherited it last week.

In the days that followed, he made it clear that nothing will be sacred in his quest to create a new base line of justice in the years ahead.

Specifically, Lozano said, he and a crack investigative team--which he is still assembling--will not stop until they solve the two major crimes that have undermined Mexico’s criminal-justice system for months:

* The March assassination of ruling-party presidential candidate Luis Donaldo Colosio in Tijuana.

* The September murder of the party’s secretary general, Francisco Ruiz Massieu, on the streets of Mexico City.

In the Colosio case, which most Mexicans believe was part of a broader conspiracy hatched by drug gangs and corrupt politicians, Lozano told legislators Wednesday that he will broaden the investigation far beyond the single-gunman theory established thus far.

Already, he said, he has new leads that indicate gunman Mario Aburto Martinez, sentenced to 42 years in prison in October, did not act alone.

The Ruiz Massieu case is even more explosive.

The former chief investigator in that case, Ruiz Massieu’s brother, left behind sealed boxes when he resigned in disgust last month. The boxes, he said, contain proof implicating the ruling party’s new president and one of Lozano’s fellow Cabinet members in a conspiracy to cover up the Ruiz Massieu murder.

Of those who know Lozano best--among them, leaders of the National Action Party who proposed him to Zedillo after the party’s flamboyant presidential candidate, Diego Fernandez de Cevallos, turned down the post--few doubt his ability to tackle, perhaps even topple, the most corrupt forces in the land.

“Tonio is a very serene person and one who doesn’t lose his head,” said Castillo, using Lozano’s widely known nickname, in an interview this week with Mexico’s prestigious weekly magazine Proceso.

An amateur boxer in his youth who fought his way from lower-middle-class roots to the top of the nation’s largest and oldest opposition party, Lozano impressed party leaders like Castillo with hard work and honesty.

“He’s very human in his manner, straight and very honest,” said fellow PAN lawyer Juan de Dios Castro. “And because of that I once told him: ‘You don’t have any enemies.’ ”

As if conceding that his future may be different, Lozano found himself saying during a farewell toast at party headquarters, “And with the help of God. . . . I hope to succeed.”