Two nights earlier, a pair of boys were stabbed in a nearby parking lot. The young man, a soccer instructor, virtually a kid himself, can't stop thinking about it, especially with all these little children around, under his care.

The police have made no arrests, but on the soccer field, 20-year-old Pedro Salmeron and several of the youngsters he coaches believe the stabbings are gang-related, one Salvadoran group targeting another.

There hasn't been a slaying in their neighborhood since 1994, but, after a lull, serious gang problems have returned to the largely Hispanic immigrant community of Culmore, an island of privation and tension amid a sea of middle-class comfort in Fairfax County.

"The [gang] mess was bad here around the early '90s and then went away," says Fairfax County police officer Paul Alexander, a longtime bike patrolman around Culmore who recently became its crime prevention officer. "But it's back now -- been back for six months, maybe a little longer. You have kids with guns, machetes, bats. We don't know where it's going."

And neither does Salmeron, who has the looks and loose stride of a teenager, utterly boyish -- from a distance. The Salvadoran immigrant, a soccer star at J.E.B. Stuart High School here who then briefly played professionally back in his homeland, got the call a few months ago when a group of Hispanic business leaders decided to put up $20,000 for a soccer mentoring program staffed by the county recreation department.

Five afternoons a week, 40 or so campers ages 6 to 13 gather with Salmeron, who is equal parts coach and aspiring, if weary, street savior, trying to keep his players away from gangs and out of trouble. It's a crapshoot at best, he thinks.

"One in five," he often says. "If I can save one kid out of five from getting into gangs or other bad things, I'll feel good, because anything can happen around here."

On the map, "here" can be found just a couple turns off Leesburg Pike, with its string of innocuous strip malls lining the way from Seven Corners to Baileys Crossroads. You go around a little curve and enter this other America: four clonish apartment complexes housing about 4,000 people, 85 percent of them Hispanic. The Salvadorans are the largest bloc, with Nicaraguans, Guatemalans and Mexicans mixed in.

In all, according to police and community leaders, there are 54 ethnic groups in Culmore -- among them, refugees from Vietnam and Thailand, and smaller pockets of Somalians and Pakistanis -- with the attendant cultural friction and problems that often accompany close-quarter diversity.

"We got a lot of people here, some of whom didn't get along too well in the old days," says Jack Smith, who manages one of the apartment complexes. "You need something like soccer to bring kids together. But the gang trouble has been an off-and-on thing. . . . Right now, it's back on. So you'd hope that anybody working at the soccer program is aware of that."

Salmeron knows. At this moment, he and a boy stand together on a makeshift soccer field at Bailey's Elementary School, its crabgrass riddled with bald spots and flecked with broken glass. The harsh midafternoon sun glints off the shards.

Salmeron has a thought about the parking lot stabbings, which happened just outside a convenience store he frequents. "Knife," he says matter-of-factly. "It wasn't a machete; I know machetes. It was a knife. . . . A bunch of gang kids getting another gang kid."

A former gang member himself who beat up people and broke into cars, he alternately packed a knife, a machete and a gun in those days. His guess about the weapon used in the recent stabbings therefore carries much weight to those listening. "Yeah, a knife," he says firmly. "Definitely. And one of the kids is on the critical list."

This bit of information freezes the boy, who has been eavesdropping while trying to dribble a soccer ball on one foot. "Critical?" 11-year-old Santiago Perez mumbles.

They are the same height, this man and boy, about 5 feet 5, as well as cousins, but that is where the similarity ends. Wide-eyed Santiago, with his moppish black hair combed straight down like a Beatle's, has baby fat and innocence left. The wiry Salmeron looks old beyond his 20 years up close, with crow's feet beneath small eyes that peer hard and miss little.

How much can a soccer coach do for children so vulnerable? he wonders. Just the night before, a new gang boldly spray-painted its insignia over Culmore's apartment buildings and dumpsters, staking out its turf just 60 feet from where Santiago lives with his parents and little sister.

"The gangs are starting to move against each other," says Alexander, the police officer. "And over what? It's about turf, just kids looking for trouble."

Salmeron feels their influence creeping ever closer to his soccer field. One of his players flashed a gang sign today, either a show of bravado or a threat. Whichever, it told Salmeron how close he might be to losing that boy.

"The kid is a troublemaker and just 11," he says sadly. "But that's old enough. That's about when they try to get kids to join. Eleven, you know, is Santiago's age. The gangs might be coming for Santiago soon."

Actually, gang members already have approached Santiago. It's no surprise: He's broad-shouldered and rugged and looks like he can brawl. Around Culmore, word is he can take care of himself.

Santiago marvels, flattered yet nervous, at how the gangs have tried to entice him. "They say they'll give you things -- money, candy, dogs. They ask you if you want to come with them. . . . I just said no."

"No for now," Salmeron adds. "Because you never know what will happen."

The boy has gone back to kicking the soccer ball. A car screeches into a parking lot. The coach looks over the boy's shoulder, hyper-alert, like a bird watching for predators.

It is Salmeron's second trip to the field this day. Earlier, he and seven fellow coaches handed out the daily free lunches. Nearly every child came today. They ate quietly, ravenously.

"They don't get lunch most of the time," Salmeron says. "Their parents are usually both gone at lunchtime; they're out working."

At lunch, as during soccer practice, nearly all the faces are Hispanic. In Culmore's stubborn social chasm, the black, Asian and white teenagers who shoot hoops on an adjoining basketball court usually decline to toss back errant soccer balls, preferring to turn their backs on children, and a game, not their own.

Camp attendance peaked at 57 but has settled at around 40, far below the 200 hoped for by organizers. There is not a single Asian or Anglo face, and only three African American children most days. This imbalance has not upset the program's Hispanic organizers.

"In Fairfax County, Hispanic kids aren't getting nearly the funding they need or deserve," says Dario Marquez, with the Hispanic businessmen's group. "We want to fund programs where the majority of our dollars are going to help Hispanic kids. . . . We're not going to allow these kids to slip away because of neglect."

Pedro Salmeron cautions against pinning too much hope on one program, one summer.

What the world outside Culmore doesn't understand about gangs, he believes, is just how much they look like destiny to a boy being nudged ever closer to the streets by friends and his own hunger to stand out among the faceless inside Culmore.

"They don't feel a part of anything," Salmeron says. "They may even be born in America, but they're still here [in Culmore], and there's just trouble here for a lot of them."

Salmeron looks at Santiago and sees himself at that age, when he first set foot in the United States and Culmore. Knowing little English and struggling in school, he took refuge in friendships with other Salvadoran youths, some of whom already had found identities in gangs. By age 13, he had joined, too.

"It's real easy to fall in," he says. "I was beating up people. I was headed for trouble. Then I started playing soccer. It got me out. Not everybody can be good at soccer, but I tell the kids, `Work hard at something.' "

Another car cruises the parking lot, another group of teenagers eyeing his boys. "You gotta be careful," Salmeron tells Santiago, who usually goes shy at such moments, leaving the coach to wonder what he's thinking, where he's going.

"I'm just here," the boy says when asked. "Culmore."

It is his universe, the only home he has known. A place like Maryland sounds as far away to him as France. Born in Galveston, Tex., to a Salvadoran mother and a Mexican father who came to Culmore when Santiago was 2, he is one more first-generation American child looking to slalom his way around trouble here.

His father, once a gang member in Mexico City, today is a restaurant manager determined that his son stay out of the gangs. "Doing things like soccer will be good until I can get Santiago and the rest of my family out of Culmore," he says. "We gotta get out soon. . . . I see these gangs coming around these last few months and I know it could mean trouble for my son. . . . I've been there."

Relatives regularly lecture the boy. "My godfather, Manuel, keeps telling me that if I get in a gang, I got a good chance of ending up in the hospital, the graveyard or jail," he says. "And I got coach talking to me."

But even in these moments, Salmeron feels Culmore's despair pressing down on all of them, pulling on angelic-looking boys who, while wanting to buy his rap, sometimes fear they can't escape what feels inevitable. "I think Santiago will make it," he says, "but there are others I don't know about." He points to the boy who has been flashing the gang signs.

The 11-year-old saunters over. Asked whether he might join a gang someday, he answers casually: "I don't want to because you might end up dead, but my life may change. I might want to. I might have to be. Things change, you know."

The boy's cousin, standing next to him, echoes his thinking. "I want to stay out," he says, "but maybe you can't."

The two boys are certain about nothing, just like Salmeron, who has no delusions, who has conditioned himself to expect much disappointment in Culmore and to relish the small, fleeting victories.

He makes a point, after each soccer practice, to walk a couple of the smallest children the half mile back to their apartments.

On one such afternoon, Santiago rushes up, comically bumping him and roughhousing as a way of hanging out with him a few minutes longer.

The man and the boy walk as stone-faced teenagers stare at them from a car in the parking lot. Every day, Salmeron makes the walk. Every day, he waits to see which way the boy will go.