Tecate, Mexico

Adrug-sniffing dog pulled the U.S. Border Patrol agent to a rusty cargo container in the storage yard just north of the Mexican border. Peeking inside, he saw stacks of bundled marijuana and a man with a gun tucked in his waistband.

The officer and the man locked eyes for a moment before the smuggler scrambled down a hole and disappeared. By the time backup agents cast their flashlights into the opening, he was long gone, through a winding tunnel to Mexico.

U.S. authorities called a trusted friend on the other side, Juan Jose Soriano.

The deputy commander of the Tecate Police Department gathered the entire shift of 30 officers at the decrepit police headquarters on Avenida Benito Juarez. Soriano knew any of them might leak information to the tunnel’s gangster operators. So he took their cellphones and sent them away on a ruse about a car chase near the border.

The veteran officer told only a few trusted aides about the tunnel. Later that day, the officers went into the U.S. and traversed the length of the passageway to an empty building, where they found computers, ledgers and other key evidence.

For U.S. authorities, it was an encouraging example of cross-border cooperation in the drug war. For Mexico’s crime bosses, it was a police victory that could not go unpunished.

That night last December, while Soriano slept with his wife and baby daughter, two heavily armed men broke into his house and shot him 45 times. The 35-year-old father of three young daughters died in his bedroom. He had lasted two days as the second-in-command of the department.

The death of a police officer is generally greeted in Mexico with a knowing smirk. All too often, it is assumed the cop in question was playing for both sides in the raging drug war that has claimed at least 2,000 lives in Mexico this year.

But all indications, from U.S. and Mexican sources, suggestthat Soriano was among the good ones, poorly paid but somehow immune to the lure of big money and the threat of deadly firepower from Mexico’s violent drug gangs.

Cooperation with U.S. law enforcement ranges from secretive intelligence sharing to high-profile raids and arrests. It is aggressive police work that runs the risk of death for honest cops.

An intense, soft-spoken man, Soriano struggled for years to clean up the troubled department. But his corruption-busting ways earned him only contempt from many cops. At the small shrine to fallen officers in the courtyard at police headquarters, Soriano’s image is conspicuously absent.

“It’s a shame,” said Donald McDermott, a former Border Patrol assistant chief who worked with Soriano. “He was one of the good guys. . . . His untimely demise was a blow to border enforcement on both sides of the border.”

A city of 120,000 tucked in the rugged mountains 40 miles east of Tijuana, Tecate is best known for its tree-lined plaza and beer brewery. But its tranquil veneer masks its reputation as a hub of organized crime groups that use the surrounding area of boulder-strewn peaks and remote valleys as a launching pad for smuggling drugs and humans.

The 200-member police department has long been suspected of functioning as an arm of the drug cartels, providing protection and ensuring that smuggling routes remain open along the 75 miles of border for which the department is responsible.

Soriano stood apart: an aggressive, disciplined lawman who aspired to become police chief, according to law enforcement sources on both sides of the border. Unlike most Mexican cops, he had a degree in police science. And he spent three years working for Grupo Beta, a federal immigrant-safety force with whom he once saved 65 immigrants in a snowstorm.

In 2003, Soriano took charge of Tecate’s SWAT-like special response team. In a break from past practices, he reached out to U.S. agencies for training opportunities and cross-border crime fighting.

Soriano’s officers arrested border bandits, disrupted smuggling operations and went where cops hadn’t gone in years, say U.S. and Mexican sources who spoke on condition of anonymity, fearing retaliation.

Soriano was a go-to source for the U.S. Border Patrol and other agencies and was a regular at binational meetings, where he shared information with his U.S. counterparts. “He wanted to do things the right way,” said one Mexican law enforcement source. “But that was a problem for many people.”

Police brass reassigned Soriano to a desk job in 2005. “They took away his wings. They weren’t ready for where he was going,” said one U.S. law enforcement source.

Late last year, Tecate’s new mayor salvaged Soriano’s career, asking him to take the No. 2 job at the department. Law enforcement contacts across the border applauded the move and didn’t wait long to restore ties.

This time, though, the stakes were higher.

A well-concealed tunnel can generate tens of millions of dollars in drug profits for traffickers, who pay huge amounts of protection money to keep them open and threaten anyone who talks about their location.

It was crucial to quickly find the opening of the tunnel discovered that December morning. U.S. authorities didn’t want the operators to have time to clear out the drugs and other evidence. In other tunnel cases, Mexican authorities had been slow to respond, allowing crime bosses to abscond with drugs.

Soriano took immediate action. After confiscating the cops’ cellphones, he dispatched them to the four-lane border crossing and told them to look out for a fugitive trying to flee from California authorities. Then he and several trusted officers started searching for the tunnel in homes and businesses near the border. He kept a close watch on crooked cops, who he feared would slip away to warn the tunnel operators.

The search failed. Someone would have to traverse the length of the passageway to find the opening.

Soriano volunteered seven officers. They crossed into the U.S. and descended into the tunnel while U.S. and Mexican authorities waited for them to surface in Mexico. About 45 minutes later, the Mexican team climbed up the 80-foot-deep shaft into a vacant two-story building a block south of the border.

A Virgin of Guadalupe picture hung near the opening. Nearby were computer monitors and scribbled ledgers. Soriano, alerted by a radio call from his team, arrived at the building just ahead of the crush of reporters and other police. Mexican federal agents took over the crime scene.

At about 2 a.m. the next morning, a convoy of vehicles drove down the deeply rutted dirt road leading to Soriano’s modest house, which was decorated with a string of Christmas lights. Two men armed with AK-47s broke in. Soriano jumped out of bed, but the men stopped him before he could grab his weapons in the hallway.

Soriano seemed to recognize his attackers and begged them not to shoot, a source said. But the men opened fire, the spray of bullets coming within inches of Soriano’s year-old daughter sleeping in the crib by his bed.

Since Soriano’s death, relations between the Tecate Police Department and U.S. agencies have been almost nonexistent. The force doesn’t have a liaison officer, and the border lands are more lawless than ever, Mexican sources say.

Soriano’s slaying sent a message to other cops who would dare cooperate with U.S. authorities.

That was clear at Soriano’s funeral, where many cops seemed to be celebrating his death, said one person who attended. Some laughed, while others chatted loudly in gestures of disrespect.

Mexican authorities suspect police were involved in the slaying, either as the triggermen or the lookouts for hit men. Nobody has been arrested in the case.

Meanwhile, the tunnel investigation has stalled. There have been no arrests, and it is unknown who was behind the construction and financing of the passageway.

On the day of the tunnel discovery, Soriano turned over a largely intact crime scene. But soon, dozens of soldiers, police, federal agents and reporters gathered to marvel at the sophisticated lighting and water pumping system. Other unidentified people seemed to linger for no apparent reason, said U.S. and Mexican sources.

The computers and other evidence had vanished.

Soriano once wrote on an employment evaluation that he wanted to be a police commander and lead a team of loyal, aggressive cops whom he would treat as friends. “I want to be surrounded by honest police who would never betray anyone.”

richard.marosi@latimes.com

Times staff writer Robert Lopez contributed to this report.