U.S., Mexico Law Officers Attend Slain Chief’s Services : Tijuana: Probe into police leader’s ambush appears to falter. Six suspects freed. Seventh held on other charges.

This violence-torn city Saturday mourned its fallen police chief, a newcomer to police work whose defiance of government corruption and organized crime may have led to his death.

Top Baja California officials and representatives of U.S. law enforcement attended services for Jose Federico Benitez Lopez, who was gunned down along with his bodyguard in a highway ambush Thursday night.

“They were clean, honest and brave men,” said Mayor Hector Osuna Jaime, who appointed Benitez, a 42-year-old lawyer and former factory administrator, to his youthful Cabinet with a mandate to reform and modernize the city police. “The society is tired of this horror story.”

Meanwhile, the investigation of the slaying seemed to founder Saturday. The state judicial police released six of the seven suspects arrested in a manhunt near the crime scene, citing lack of evidence. The seventh was being held on apparently unrelated fraud and weapons charges, according to a news release.

Two of the suspects had been described earlier Saturday as paid enforcers working for the federal judicial police, according to a government official. Known in Mexico as aspirinas , such quasi-police officers are often involved in corruption and clandestine violence.

It was not yet clear whether the slaying was connected to drugs, Benitez’s involvement in the probe of the murder of a presidential candidate here last month or a sweeping purge of corrupt city officers, Mexican and U.S. law enforcement officials said.

“What we need are less theories and more facts,” said U.S. Atty. Alan Bersin of San Diego, who attended the funeral.

Investigators are examining several scenarios, sources said. One report indicates that the chief was slain because he had learned of drug-related misconduct by federal police officers, an official said.

Another theory is that Benitez ran afoul of the ruthless Arellano cartel of Tijuana, which was involved in a shootout March 3 between federal agents and state police officers who were protecting a drug lord. The gun battle resulted in the creation of a joint task force by the Drug Enforcement Administration and the FBI that is working closely with Mexican authorities.

The Tijuana police do not investigate drug crimes, which come under federal jurisdiction. But, under Benitez, a SWAT-like city unit known as the Grupo Tactico had cracked down on street-level trafficking. Benitez’s combination of integrity, inexperience and aggressiveness--he often personally supervised operations--earned him numerous enemies, officials said.

Benitez was also outspoken about his doubts concerning the federal investigation of the March 23 assassination of Luis Donaldo Colosio, the presidential candidate of the Institutional Revolutionary Party. Benitez was scheduled to meet Monday with a Mexican congressional commission that is conducting a separate probe of the Colosio case.

Whatever the truth, the third spectacular eruption of violence here in the last two months has worsened a climate of fear and anarchy, according to Javier Gonzalez Monroy, a city councilman.

At the funeral Mass on Saturday morning, tense security guards armed with AK-47 rifles hustled Gov. Ernesto Ruffo Appel, Mayor Osuna and other dignitaries into Our Lady of Guadalupe Church across from City Hall, where they joined about 800 other mourners. The eulogy was delivered by Father Ramon de la Cerda, who condemned the killers as “irrational, criminal people without heart” and said the mourners “who continue to live in this vale of tears must hope for a more peaceful, less conflictive life.”

A subsequent outdoor ceremony was attended by dozens of officers from agencies on both sides of the border. Ramrod-straight officers ritualistically shouted “Present!” when a speaker called out the names of Benitez and the bodyguard, Ramon Alarid Cardenas.