Watching From the Shadows : Border: An elite Mexican police unit is keeping an eye on migrants and the people who victimize them. Its work has produced a rare consensus of support on both sides.

The undercover policeman stands in the shadow of the border fence, watching his countrymen go north.

Wraiths in the fog, they surge up the concrete levee of the Tijuana River. Their furtive progress is lighted by bonfires, spotlights, a swooping U.S. Border Patrol helicopter. They scramble up the 10-foot corrugated metal fence and pause--suspended between Mexico and the United States, between a desperate past and an uncertain future.

Comandante Joel Alcaraz scans the crowds, with the gaze of both hunter and shepherd. He is searching the nightly advance of potential victims for predators--robbers, rapists, swindlers. And crooked cops.

“Every one of these migrants is a story,” says Alcaraz, a serene former homicide detective in a leather jacket, wire-rim glasses glinting, breath steaming in the cold. “They save all their money. They sell everything--the chickens, the cow, the little house--so they can bring their whole family. And they get robbed.”

Alcaraz belongs to Grupo Beta (Beta Group), an elite Mexican police unit with the most dangerous beat in the Tijuana-San Diego metropolis: the border.

In 16 months, this extraordinary law enforcement experiment has improved U.S.-Mexican relations, reduced violence and remained generally free of misconduct and corruption, according to San Diego police, the U.S. Border Patrol, U.S. conservatives, immigrant-rights watchdogs in Tijuana and San Diego, and the border crossers themselves--a rare consensus among the fiercely polarized voices of the region.

“It’s better now. Before, it was all thugs and bums around here,” said Chuey, a chubby, sleepy-faced teen-ager who charges $85 a person to guide immigrants to a San Ysidro fast-food joint where rides to Los Angeles await.

Gustavo de la Vina, chief Border Patrol agent in San Diego, calls Grupo Beta “a dedicated bunch of guys and gals. They are having a lot of impact. They have made it a lot safer for our people and illegal aliens and everyone concerned.”

Despite the praise, the 36 officers of Grupo Beta--culled from federal, state and local police forces--find themselves on treacherous and lonely turf. At a crucial time in U.S.-Mexican relations, they work under a political microscope.

They have clashed with other Mexican police by cracking down on renegade officers who once roamed the area extorting and abusing migrants.

They also navigate a narrow course between their government’s policy, which opposes interference with the emigration of Mexican citizens, and U.S. authorities who ask for more help against drug runners and smugglers of illegal immigrants.

“It is a delicate question,” said Javier Valenzuela Malagon, a psychologist and former university professor who heads Grupo Beta.

As Comandante Alcaraz sweeps his flashlight beam across the fence just east of the San Ysidro Port of Entry, his radio growls under his jacket. From U.S. territory, Border Patrol agents advise that they are chasing an old Plymouth south on Interstate 5 toward the crossing.

Alcaraz hurries back to his Ford LTD. The car lunges down a dirt road and joins three other Grupo Beta cars converging like sharks on the Mexican customs station. They intercept the fleeing Plymouth just after it speeds past the inspection booths.

The undercover officers--wearing bulletproof vests, jeans, dark glasses, cowboy boots and Army jackets--haul out the driver, a suspected immigrant smuggler.

There is surprise and realization on the driver’s face: The rules have changed south of the border. Before Grupo Beta, it was highly unlikely that a Border Patrol pursuit would end in a suspect’s capture by Mexican police.

The new cooperation is not without controversy.

Recently, Grupo Beta moved in to stop cross-border freeway stampedes of illegal immigrants through the Mexican customs station into southbound traffic at San Ysidro. A week of news coverage in January had made the freeway charges an international embarrassment during negotiation of the proposed North American free-trade pact.

“This was one of the most rapid diplomatic responses of the Mexican government that I have ever seen,” said Baja California human-rights prosecutor Jose Luis Perez Canchola, an authority on immigration issues. “These are special times in which the Mexican government does not want to disturb the negotiations. Everything is negotiable.”

Critics of the Border Patrol say the freeway charges resulted from a shift in the immigration flow caused by the newly fortified border fence and tougher enforcement along it, rather than an increase in the number of immigrants. They say the agency inaccurately presented the phenomenon as evidence of illegal immigration gone wild in order to exert pressure on Mexico.

“I am against the Mexican government doing the dirty work of the Border Patrol,” Perez Canchola said.

Although he praises Grupo Beta for cleaning up a nether world of slums and canyons, where rapes occurred three times a week, Perez Canchola criticized the use of the undercover officers to end the freeway crossings, saying it detracts from their crime-fighting task and amounts to helping the United States stop illegal immigration.

“Of course, there is a fine line between combatting the polleros (alien smugglers) and persecution of migrants,” he said. “There is a great deal of criminality among the polleros ; there are many who cheat and abuse people.”

Valenzuela, the Grupo Beta leader, said his officers were brought in because of their knowledge of the smugglers who organized the freeway charges.

“Our fundamental mission is protection of the migrant,” he said. “For us, crossing the border is not a crime. At the same time, that does not mean people can cross anywhere they want, especially in dangerous places such as the customs station.”

Uniformed immigration agents will replace Grupo Beta officers at the customs station within weeks, Valenzuela said.

Smuggling immigrants is a crime in Mexico, but Grupo Beta concentrates on large-scale operations that tend to involve official corruption, kidnaping and extortion of immigrants, Valenzuela said. It monitors small-time smugglers because some are valuable informants, and others sometimes mistreat their clients.

U.S. authorities say the border unit has contributed to encouraging statistics: Homicides on the U.S. side of the border area dropped from 10 in 1990 to none in 1991. The amount of money spent replacing windshields of Border Patrol vehicles has shrunk by half because the Mexican officers break up rowdy, rock-throwing groups. Assaults on Border Patrol agents have declined 39%, and drug seizures are up.

Grupo Beta’s mission recalls the swashbuckling undercover team created by the San Diego Police Department in 1976 to fight rampant violence against illegal immigrants. Its harrowing experiences are chronicled in Joseph Wambaugh’s book “Lines and Shadows.” The Border Alien Robbery Force, as it was known, engaged in many shootouts with bandits and a few with Mexican police. It was eventually disbanded.

A uniformed version of that San Diego team operates today: the Border Crime Intervention Unit. Instead of shooting at each other, BCIU and Grupo Beta officers shoot together--at a San Ysidro firing range. They also maintain constant radio contact, an unprecedented step, and share criminal intelligence.

On a recent Friday night, the BCIU men, known as “ Los SWAT” in Tijuana, crossed the border at the port of entry to visit the cramped Grupo Beta offices. Officers made jokes and discussed a robber with a shotgun who has been operating just north of the fence in San Ysidro. The conversation was in Spanish.

“It is an excellent relationship,” said Lt. Adolfo Gonzalez of BCIU, which has donated bulletproof vests and radios to its Mexican counterpart. “It is one of the most exciting projects I have worked in. This is police work of the 21st Century.”

Both units take pains to respect international boundaries when in the field, Gonzalez said. “At most, we extend handshakes across the border, but that’s it.”

Grupo Beta officers generally work in plainclothes teams of three. They melt into crowds on foot, gathering information from vendors and polleros, shadowing and questioning suspected thieves, drinkers and other potential lawbreakers.

In addition to facing the bandits, the officers must defend migrants from other Mexican police. They have arrested fellow officers and filed reports on others suspected of robbery and extortion.

Although officials are reluctant to discuss it on record, tensions between Grupo Beta and fellow police agencies are well known in Tijuana. Especially in the early months, as the unit established control of what had formerly been lucrative hunting grounds for the corrupt, it has been the target of threats and ostracism.

Some municipal police officers have failed to respond when Grupo Beta needs backup, according to sources close to the unit, although they said a recent conciliatory meeting between higher-ups has improved relations.

And, for several months, a handwritten sign in the window of the office where Baja state judicial police pick up their paychecks ridiculed Beta members as turncoats, sources said.

The enmity has made Grupo Beta officers more united, one officer said. “We are like a family.”

They are also carefully screened, trained and monitored. As an incentive against corruption, they make about $1,000 a month--about three times what municipal police make and about double what state police make.

Several officers have been dismissed because of allegations that they tried to shake down migrants or suspects, Valenzuela said.

About a year ago, a member of Grupo Beta was found shot to death in a rural area. But the murder took place off-duty, Valenzuela said. An investigation found no connection to the officer’s work on the border unit; there may be a connection to his previous post as a homicide investigator in Sinaloa, a state wracked by narcotics-related violence and corruption, Valenzuela said.

In Tijuana, official corruption is regularly dug up and denounced by aggressive local journalists and human-rights activists. The city’s most outspoken police critics say that Grupo Beta appears to have maintained high standards of conduct.

“Grupo Beta is demonstrating how, with political will, there can be a police force free of corruption that does its job well,” said Tijuana human-rights advocate Victor Clark Alfaro. “It is an example for other Mexican police agencies.”

The commander of this quixotic venture is a slight, cerebral psychologist with a background in ‘60s-era student activism and a poetic sense of social commitment. The 40-year-old Valenzuela spent 10 years as a university professor in Mexico City, eight years as a community organizer with indigenous groups in rural provinces.

The despair and dignity he saw deepened his sympathy for Mexico’s impoverished migrant population. He got a chance to test his ideals against the reality of police work after his appointment in 1988 to the Interior Ministry of incoming President Carlos Salinas de Gortari.

Mounting alarm over border crime and chaos was seen as a threat to the free-trade agreement. In the reform-oriented atmosphere fostered by Salinas and Baja Gov. Ernesto Ruffo Appel, federal, state and city officials agreed that Valenzuela, a Tijuana-based administrator for immigration services, should head a new multi-agency border force.

“It had to be distinct from traditional police,” Valenzuela said. “It had to be a professional, honest project with a mystique of protection and service. In the moment that we gave in to temptation, we would become another group like all of those who prey on people at the border. . . . It had to be an environment of open dialogue and friendship. We talked about our frustrations, our families, why we became police officers.”

Officers say the system is unlike anything they have encountered in law enforcement in emphasizing group discussions and sensitivity to the public. Unlike counterpart U.S. units, which have been involved in periodic controversial shootings over the years, Grupo Beta has yet to shoot anyone.

That is partly because officers are less likely to encounter armed assailants in Mexico, according to officials in both units, and partly because of strict rules and considerable restraint, as reflected by an incident Comandante Alcaraz described at a recent afternoon roll call.

During the previous midnight shift, he said, officers were patrolling a gritty neighborhood just west of the customs station, where every night migrants fill the streets, cut through yards and climb walls and fences. The officers heard gunfire.

They tracked the shots to an alley next to a small hotel and confronted a drunk man with a gun, who was apparently enraged at migrants crossing his property. Threatening to kill the officers, he fired once again; the officers took cover, then rushed him and wrestled away the gun, Alcaraz said.

“They had the courage to disarm him,” Alcaraz told the somber group. “He had the total advantage. He had already shot at them. And they didn’t use their guns. . . . They showed a lot of maturity, exposing their lives in this way.”

If Grupo Beta’s effectiveness continues, the unit will expand. The government plans to build a larger, modern headquarters to replace an existing makeshift office and jail space. Federal officials have also discussed reproducing the idea on Mexico’s borders with Texas and Guatemala, and creating an academy, Valenzuela said.

“We hope to have influence on other police agencies, in order to reconsider the traditional forms of police organizations,” he said. “We think this idea of coordinating the three levels--federal, state and city--is a valuable concept. We are stronger when we work together. . . . We can keep growing, little by little, with a self-critical attitude and moving always toward the idea of professionalization.”

When Alcaraz goes off duty at midnight, he is replaced at the muddy levee by Francisco, 38, an 18-year veteran of the Tijuana municipal police, and Eva, a 23-year old rookie, the only woman in the unit. Would-be smugglers and bandits often mistake them for husband and wife, offering Francisco a special discount to help his “senora” over to the other side.

The two undercover officers asked that their last names be withheld.

Francisco and Eva come across two street urchins emerging from the shallow, fetid waters of the river, extremely wet boys with feral faces, ages 8 and 10.

“Don’t you know the water is full of garbage and germs that can make you sick?” Francisco asks, serious brown features betraying paternal concern beneath his baseball cap. “Do your parents know where you are? What are you doing?”

“We came to see how they jump the fence,” one boy replies.

Eva takes them to the office, where they will be turned over to social service workers.

Francisco remains. Roving in the crowd, he abruptly stops and questions three young men who he says look like trouble.

He has a good eye. Two of the youths, who sport buzz-cut hair, T-shirts and low-slung pants in the cholo gang style, have just been deported from the United States after serving time in the Los Angeles County jail. They show him their deportation papers.

The tall youth was locked up for armed robbery; the short one with the plastic cross around his neck was convicted for selling cocaine.

“We aren’t doing anything wrong,” the short one insists, shivering. “We were just thinking about crossing again.”

“It’s not a crime to be out here,” Francisco tells him. “It’s not a crime to cross the border. But if you are going to be here, we don’t want you causing any trouble. We don’t want you bothering anyone.”

He lets them go. They wander over to a group of people warming themselves at a bonfire, and are soon regaling their audience with loud stories about jail.

They glance back occasionally toward the policeman watching from the shadow of the border fence.