BY GLENN GARVIN

 MEJICANOS, El Salvador -- Even in one of the most violent countries of the world,
 this scruffy working-class suburb of the capital was something special, a place so
 utterly lawless that street gangs cordoned off entire neighborhoods and charged
 people to go in and out.

 That makes the statistics all the more startling: Murder, down 67 percent.
 Carjackings, down 42 percent. Robbery, down 22 percent.

 ``This was one of the most dangerous places in El Salvador,'' said officer William
 Romeo Portillo as his patrol car rolled along the no-longer-so-mean streets. ``Now
 we have one of the lowest crime rates in the whole country.''

 The reason, very literally, is Portillo and a few dozen other cops, the advance
 guard of a U.S.-funded experiment that may change the face of law enforcement
 in crime-ridden Central America. In a radical break with tradition, the police here
 left their stations to walk beats and patrol the streets.

 In a region where all the police forces evolved from the army and still maintain a
 barracks mentality, sending officers out to work the streets was a change so
 profound that Salvadoran authorities acknowledge they tried it only out of
 desperation.

 ``We had no tradition of community patrolling here,'' said Francisco Bertrand
 Galindo, the minister of public security. ``The police were sitting in their stations,
 receiving complaints. Maybe you had one guy patrolling around, but he never
 talked to anyone.''

 HUNDREDS IN TRAINING

 But the results of the experiment in Mejicanos and a follow-up program in three
 neighboring cities have been so spectacular that Salvadoran authorities are now
 training hundreds more officers in community police work and plan to implement it
 all over the country.

 They are urging their neighbors to give it a try, too.

 The end of the civil wars that wracked this region during the 1980s left hundreds of
 thousands of trained combatants out of work, and many of them have turned to
 crime. Crime rates have skyrocketed throughout Central America, and police
 forces in other countries, working from the same military model as the one in El
 Salvador, have been equally ineffectual.

 ``I think the success of this program could serve other countries very well,'' said
 police Subcommander Hugo Ramirez, who oversaw the first six months of
 community patrolling in Mejicanos. ``I know Nicaragua and Guatemala very well,
 and I think the experience we've had here could be very good for them.''

 Salvadoran officials admit they would never have tried community policing if they
 hadn't been desperate. After a 13-year civil war ended in 1992, the country was
 not only awash in weapons and unemployed men who knew how to use them, but
 the police were spectacularly inept.

 OLD FORCE ABOLISHED

 The peace treaty that ended the war also abolished the old police forces -- widely
 believed to have been linked to right-wing death squads -- and called for a new
 force.

 In the rush to get cops onto the street, the government did little screening or
 training. More than 300 cops were fired for misbehavior last year, and another
 2,600 suspended. Hundreds of police cars rest in junkyards, wrecked by officers
 who barely know how to drive.

 The U.S. Justice Department, which helped the Salvadorans set up the new force,
 had been pushing the country for years to try community patrols. But little was
 done until Louis Cobarruviaz, the former police chief of San Jose, Calif., arrived to
 head a Justice Department office known as the International Criminal Investigative
 Training Assistance Program (ICITAP).

 TRACK RECORD

 Not only did Cobarruviaz arrive just about the time El Salvador's crime problem
 peaked, but his experience in San Jose -- where crime fell 46 percent during his
 tenure -- impressed the rank-and-file police who would have to carry out the
 community policing plan.

 ``Most of the people who work for ICITAP are from the FBI,'' said Rodolfo Canjura,
 the police subcommander who now overseas Mejicanos. ``They know more about
 investigations. But Cobarruviaz is a guy with street experience, and that made a
 difference.''

 Backed with $2.5 million in U.S. funding, Cobarruviaz preached the same
 message here that he did when he took over the San Jose police: ``You've got to
 attack crime at the front end. That doesn't mean detective work; it means patrols.
 That's what we're doing here, too. These patrols are preventive in nature. Very few
 people will kill someone in the presence of a cop.''

 But even when the Salvadoran police accepted his philosophy, Cobarruviaz
 discovered, they still needed training in even the most basic skills -- for instance,
 interviewing a witness.

 ``In America, we learn these things by experience,'' Cobarruviaz said. ``Here, they
 haven't had any experience.''

 But they picked it up fast. Put onto the streets of Mejicanos first in patrol cars,
 later on bicycles and foot, the cops quickly learned that getting to know the
 community paid big dividends.

 LOCAL KNOWLEDGE

 ``The people in the neighborhood have a pretty good idea of their situation,''
 Ramirez said. ``They know who's stealing, who's selling drugs, who's beating his
 wife. We are taking advantage of that.''

 Using a questionnaire approved by the Salvadoran Supreme Court, the cops
 created their first rudimentary intelligence data bank, questioning suspicious
 characters and noting nicknames, tattoos and other identifying characteristics,
 then transferring the information to a donated computer. It paid off almost
 immediately: A kidnapping ring was busted and a quadruple murder solved
 through use of the information.

 If the patrols have a downside, it's that unsupervised cops can more easily rough
 up suspects if they're inclined to. Some people say that's exactly what has
 happened.

 ``If you weren't here, they'd be beating the hell out of us for sure,'' a young man
 named Raul whispered to a reporter as cops questioned a group of suspected
 crack dealers on a recent patrol in Mejicanos. ``They just know better than to do
 it in front of a journalist.''

 But a group of residents watching as police checked the IDs said the patrols have
 reclaimed their neighborhood.

 ``The sales of drugs were practically everywhere here before the police started
 patrolling,'' said Jose Rey, a 36-year-old shoemaker. ``You couldn't go a store or
 anyplace around where they weren't selling crack. . . . I think there are lot of
 abuses of authority, that's true, but they can't just stop policing the neighborhood
 because of that.''