OFFICERS ON BORDER TEAM UP TO QUELL VIOLENCE

United States law enforcement authorities, seeking to avert a
spillover of drug violence from Mexican border cities, are cautiously
trying out new cross-border cooperation with the Mexican federal
police, according to senior Homeland Security officials. The efforts
will include coordinated operations and expanded intelligence sharing.

American border and customs agents are working more directly with the
Mexican police, the officials said, despite a history of collaboration
efforts that were compromised by leaks through Mexican authorities to
traffickers and smugglers south of the border.

American officials said they had been encouraged to try joint programs
because Mexico had shown a new openness to United States assistance
and had allowed more direct American involvement in training and
background checks of Mexican police officers.

The move toward cooperation intensified in the past year after law
enforcement leaders in both countries recognized that working
separately, they were losing ground against increasingly aggressive
and bloody Mexican drug trafficking and immigrant smuggling
organizations, American officials said.

In one experiment, United States Border Patrol agents have since
September conducted parallel daily patrols with the Mexican federal
Public Security police along an 80-mile stretch of the border around
Nogales, Ariz. Each morning, Border Patrol officials said, their
agents advise the Mexican police of the locations they plan to scout
that day, and Mexican officers patrol across the border, in what the
officials called "mirrored enforcement."

"We will call them, and we will tell them where we are going to
concentrate our efforts," Jeffrey D. Self, acting deputy chief of the
Border Patrol, said in an interview. "They will deploy on the south
side in that area."

Mr. Self described the parallel patrols in terms that evoked the
United States' military approach in Iraq. "Gain, maintain and expand -
that's the strategy," he said. "We hit a target area real hard, we
bring it under control and we leave just enough resources behind to
maintain that control."

Mr. Self said the program had led to "all different levels of
communication that have never been established before" between the
Border Patrol and Mexican Public Security agents. "The agent in the
field is speaking with Public Security on a daily basis during their
shift," he said.

While the Border Patrol's daily planning is based on classified
intelligence from many American law enforcement agencies, Mr. Self
said, American agents share less secret information with Mexico,
identifying the terrain they plan to scout on a given day.

"The whole effort is an intelligence-driven operation," Mr. Self said.
"But we don't give exact locations of our agents. We refer to common
names of geographic areas, and landmarks."

Mexico is also sharing some operational intelligence from its
agencies, American border officials said.

As part of the program, the Border Patrol has been training Mexican
police officers in Nogales, which has helped American agents to come
to know individual officers they will work with, Mr. Self said. Since
September, 36 Mexican agents have received training in urban
close-quarter combat tactics, behavior analysis and pointers on
detecting hidden compartments in vehicles, American officials said.

The Nogales program, which involves only civilian agents on both sides
of the border, is closely watched in Washington, where officials have
decided to steer antidrug efforts with Mexico away from an emphasis on
military operations. In recent weeks, after drug mayhem left dozens
dead in Ciudad Juarez, another border city, President Felipe Calderon
has revised a strategy that relied primarily on Mexican Army troops to
lead the fight against traffickers.

During a visit to Mexico on Tuesday, Secretary of State Hillary Rodham
Clinton, Defense Secretary Robert M. Gates and Homeland Security
Secretary Janet Napolitano announced a $331 million plan to bolster
Mexican civilian law enforcement agencies.

Ms. Napolitano said that President Calderon had been more open to law
enforcement cooperation than his predecessors.

"I've been working border issues since 1993," Ms. Napolitano, a former
governor of Arizona, said in an interview last week. "The level of
cooperation from Mexico, the resource commitment, the willingness to
let the U.S. provide some direct assistance, all are very different
than I've seen in the past."

American border officials chose Nogales for the new program because
after Juarez, it had been "our most chaotic environment" along the
border, Mr. Self said. An extra 318 Border Patrol and customs agents
were added for the effort. In the first six months, he said,
drug-related arrests were down (a counterintuitive sign of success),
and violent attacks on Border Patrol agents have dropped sharply.

The program does not involve local Mexican police officers from border
cities, where drug corruption has reduced some municipal police forces
to disarray.

Many Border Patrol agents remain wary of working with the Mexican
police, Mr. Self acknowledged. Agents know countless stories of
intelligence tips shared with Mexican law enforcement, which only
served to give traffickers time to get away or to set up ambushes for
officers.

"Are they plagued with corruption? Yes," Mr. Self said. "We recognize
there is a lot of work still to be done on that."

But through the Nogales training and daily consultations to plan
patrols, Border Patrol agents have gradually identified "good, honest
police on the Mexican side," Mr. Self said.

Any Mexican police officers who enter Homeland Security facilities for
training or consultations go through extensive background checks by
American intelligence.

Border officials are building on years of experience by Drug
Enforcement Administration agents, who have set up background check
programs for the Mexican federal antidrug police, according to Michael
A. Braun, who retired in 2008 as chief of operations for the drug
agency. Mexican federal antinarcotics teams take regular polygraph and
urine tests, and their personal information is regularly updated, he
said.

But security analysts noted that Mexican traffickers, who wield
threats of violence and huge amounts of cash, had managed to
infiltrate carefully selected narcotics teams in the past.

"There is always a risk they are sharing information that is then out
of their control," said Eric L. Olson, coordinator for the Mexico
security program at the Woodrow Wilson International Center for
Scholars in Washington. "They are giving information and hoping the
Mexicans will do right by it and with it."