Warden of Tijuana Prison Slain : Crime: Probe centers on gangs at notorious La Mesa penitentiary. Official is described as a gentle man who refused to use force in recent uprising.

Police on Thursday were investigating the latest assassination of a government official in this border city: the ambush murder of the director of the state penitentiary.

A gunman killed Jorge Alberto Duarte Castillo, 42, who had worked to keep the peace at the notorious La Mesa prison, in front of his modest, two-story house at 10:45 p.m. Wednesday. When Duarte arrived home , two assailants dragged him from his Volkswagen into another car, shot him four times and dumped his body about half a block away, according to Baja California state judicial police.

The investigation centered immediately on the inmate gangs who control drugs, prostitution, housing and other lucrative rackets in an institution wracked by overcrowding and violence. Called the Little Village of La Mesa, the prison has become internationally known as a surreal community of about 2,500 people--including women and children--crammed into less than two acres.

“In the penitentiary there are frequently tense situations because of high-risk inmates and overcrowding,” said Carlos Salas Aceves, the state’s director of public security and corrections. “The police are immersed in the investigation, with solid leads about which we prefer not to comment.”

Investigators believe that inmate gangs may have ordered the murder in revenge for recent crackdowns on guns and drugs, government officials said. The white- walled penitentiary in the La Mesa neighborhood remained under heavy guard Thursday, as inmates flocked to a morning Mass for the slain director at the prison chapel.

“The men were crying,” said Mother Antonia, a nun who lives and does charitable works in the prison. “He was a man of great humanity. He was very big-hearted. He was a man of prayer.”

Coming amid Mexico’s crisis of political instability and corruption, the murder raised again the specter of lawlessness in Baja California. Tijuana continues to feel repercussions from three crimes: the murder of a federal police commander in a shootout with state police and the assassinations of presidential candidate Luis Donaldo Colosio and municipal police chief Federico Benitez.

Like Benitez, Duarte--a law professor who was married with two sons--was appointed by the opposition-party administration that runs Baja. Tijuana has experienced increasing tension since the arrest of an alleged second gunman in the Colosio case two weeks ago as part of a suspected conspiracy involving the ruling party in Tijuana. Gov. Ernesto Ruffo Appel beefed up his security team recently after a rumored attempt on his life.

But Duarte’s murder appears related to vengeance, not politics, the governor said Thursday.

Among the potential suspects is Antonio Vera Palestina, one of the most powerful chieftains in the prison, a government official said. Vera is serving a 25-year sentence for the murder of a Tijuana newspaper columnist. Vera operates a small garment factory in the prison and has allegedly fought a power struggle with rival gangs.

In July, 1992, Duarte assumed control of one of the strangest prisons in the world. Rich inmates in La Mesa own custom-built homes, stores and restaurants in the congested compound and surround themselves with servants and gunslingers. The poor live in squalor and cling to their main luxury: a liberal visiting policy that permits hundreds of family members to live within the walls.

Duarte brought an unorthodox approach to this grim, but in some ways curiously humane, bastion of an authoritarian justice system. He was a gentle man, a devout Catholic who kept a large painting of Christ on the wall of his office.

Last year, when inmates took over a cellblock and fired on guards, Duarte steadfastly opposed using force. He threatened to resign if state police carried out a planned assault. The inmates surrendered after negotiating with Mother Antonia. Because of a dire shortage of funds, Duarte maintained, the only way to keep the penal time bomb from exploding was with dialogue and restraint.

“We must take the gradual approach,” he said. “This situation is very delicate and we cannot take abrupt or drastic measures.”

Following Duarte into the raucous prison yard, with its brightly-colored shops and surging crowds, was like entering a hallucination. He would greet heroin addicts, fathers carrying babies, swaggering gangsters and impoverished, frightened migrants without criminal records--La Mesa houses convicted criminals alongside the accused. His critics demanded a crackdown on corruption, misery and violence. They called Duarte naive and overwhelmed, saying he had ceded authority to the half-dozen inmate bosses.

But it was hard to find anyone who did not describe Duarte as well-meaning and deeply committed. Duarte had pointed out that, despite the volatile conditions, the prison has averted the full-scale massacres that have erupted in other institutions around the world.

He liked to talk about success stories: an inmate who become a professional boxer, thriving prison artisans, a musical group that sang happy birthday to him last year. He hoped that the construction of the chapel, vocational school, administrative centers and cellblocks during the past years would superimpose a more modern and controlled facility on the aging, often anarchic one.

“This is the reality with which I have to live,” Duarte once said.

And on Wednesday night, in a middle-class housing development on the edge of the city, that reality may have taken his life.