You never know where someone's going to park in Bentley Circle. Drivers routinely stop in the middle of the road in this Woodbridge subdivision, while young men stroll up to the cars, lean in the windows and chat. Neighbors who stare too long are quickly cursed.

"What you lookin' at?" one young man barked at a resident climbing into her car one afternoon last week. "Get your butt back in the house."

On many nights, one youth unleashes a sirenlike sound whenever a suspected police car turns into the circle. Groups of teenagers gather in front yards and on back porches, while mothers steer their children away from the empty beer cans, discarded marijuana pipes and used condoms that occasionally litter the nearby playground.

Bentley Circle wasn't always like this. As a secluded cul-de-sac of town houses in eastern Prince William County, it was a place where families moved to escape urban troubles and find a good deal on a house. "It was a very quiet and nice neighborhood," said Bonnie Crisman, who moved in with her family 13 years ago. "It was cheap, it was quiet, it was unknown."

Tension has replaced the quiet in recent years. Even as residents have struggled to keep the neighborhood safe and stable--where children could ride bicycles and play outside--some of them say the character of the place changed. Some residents said they were just waiting for things to boil over.

Then, less than two weeks ago, Natalie Giles Davis--heading to church with her two children and other relatives--found her way blocked by one of those idling cars, surrounded by one of those groups of loitering teenagers.

Exactly what happened next remains unclear. But Davis may have snapped at the teenage girls, who--police said--then jumped in their car, chased after the car Davis was riding in and beat her to death when she confronted them.

Police quickly arrested Teresa Hattie Dixon, 18, and Kurebia Maria Hampton, 16, neither of whom lived in Bentley Circle but who apparently had been visiting friends. Dixon was arraigned Wednesday on murder and malicious wounding charges. Hampton has been charged in juvenile court with murder, but prosecutors hope to try her as an adult.

The June 29 incident was the street's first public episode of violence, but it has fed the anger and frustration of many residents who say they have watched as Bentley Circle has slowly grown less civil, less stable and less desirable.

"Each year, it's gotten worse," said Lori Poore, a neighbor of the Davises. "I hate coming in and out of here."

Theresa Carter, who bought her home in 1991, wants to move but is "stuck" because she cannot sell without taking a huge financial loss.

"If you came up and saw my house, would you buy it?" Carter asked, looking to the evening sky, urging her 4-year-old daughter to bring her Big Wheel tricycle into the house. "You'd see all that is going on here and you'd want no part of it."

Reflection of Other Forces

In some ways, the situation on Bentley Circle reflects larger economic forces in Prince William County, where many neighborhoods of inexpensive town houses built in the last two decades are feeling their age and seeing stagnant or falling property values. With so many new, relatively inexpensive houses on the market, owners of older town houses have found it difficult to break even by selling, let alone to make money.

Bentley Circle's 97 homes were built in 1980 and 1981, part of the Rollingwood Village development that was finished in 1986. In the recession of the early 1990s, some Bentley Circle homeowners had their properties repossessed, Crisman said, and other owners moved out and started renting. A tide of new residents moved in, and "that's when the trouble started," Crisman said.

Carter said that with some renters came inconsistency and neglect. "No one cared about the houses, so they just treated them badly," she said.

Criminologists have found that such shifts in neighborhoods sometimes lead to social problems.

"Because people are moving in and out more frequently, you are less likely to know your neighbors," said Margaret A. Zahn, of North Carolina State University, who recently completed a 14-year study of homicide rates. "Where there's turnover, you don't get to know people, and there is not so much informal social control."

In an effort to preserve the community's sense of security, the homeowners association three years ago put in additional lighting and instituted a regular neighborhood watch shift, which has about 40 participants. They removed a basketball hoop from the playground, citing rampant problems involving teenagers from other neighborhoods playing late into the night and becoming rowdy.

Don and Veronica Fahringer joined the neighborhood watch patrol shortly after they arrived about two years ago, and Don, who is a private security guard, said he carries a .357 magnum when he walks with his wife around the community. The couple are hesitant to take their grandchildren into the park.

"We sleep in the basement sometimes during the summer because we don't want to leave the air conditioning on all night, and we open up the windows," Veronica said. "And with the windows open, there is no way to get any sleep. It's just too loud, at all hours."

The homeowners association also worked with the county police. The evening of the beating, Prince William police officer Jeff Pyck was the first on the scene because he was already in the neighborhood, meeting with a group of residents who were concerned about frequent visitors at one house on the street.

Puzzling Rage

Still, Pyck said, despite the neighbors' concerns about loitering and other irritants, crime and violence remain unusual in Bentley Circle. "We have very few calls down there," Pyck said.

That has made it all the more puzzling that an argument over double parking could have escalated into such explosive rage.

Natalie Davis had lived on Bentley Circle only about six months. She and her husband had met in Brooklyn, N.Y., and three years ago, they moved to Northern Virginia with their children Symphony and DaJour--now 4 and 2--for a quieter life. Charles Davis worked in a paint store while his wife stayed with the children.

Leica Cooper, Natalie Davis's cousin, said Davis had battled sickle cell anemia for much of her life, nearly dying on several occasions. Davis had taken medication before the July 4 weekend, so she could be home with relatives arriving for a big barbecue.

"She suffered all her life, and she wasn't supposed to live past 20 or have any kids," said Cooper, of Dale City. "She beat all odds that were put against her. Maybe if she had been stronger, she could have won this battle."

Davis had begun wondering whether her family had done the right thing in buying a home in Bentley Circle, and she frequently thought about moving, her friends said. "Natalie was starting to become concerned with the community," said Julian Grante, a friend and fellow church member, who described the neighborhood as "a mixed bag."

But despite any frustration she might have felt, Davis's relatives say it would have been out of character for her to have touched off the traffic dispute by yelling at the teenagers, as friends of the suspects say. The suspects' friends also allege that Davis struck the first blow when the cars moved to nearby Rollingwood Drive.

When the fight got underway, police say, Hampton, the 16-year-old, slammed Davis's head into the sidewalk several times, and then Dixon, 18, stomped on Davis's head.

Jean Stokes, a coordinator of the neighborhood watch, said she rushed outside and found Davis, bleeding from her right ear and with her right eye swollen. "She was in bad shape. She definitely was in bad shape. She wasn't crying or nothing, but she was in a lot of pain," Stokes said.

Both Hampton and Dixon are in jail, and family members and lawyers have declined to comment.

Dixon, of the Alexandria section of Fairfax County, had graduated from Chantilly High School just a week before the beating. She had worked at a day-care center while attending school, and one of her high school teachers, Tina Denman, said she was shocked to learn of her former student's arrest.

"She worked really hard to graduate," Denman said, adding that Dixon did not have a hot temper and that she showed no other signs of trouble. "She was just trying to decide what to do with her life."

Hampton had attended Pennington High School, an alternative school for students with behavioral or academic problems, but had been kicked out recently for fighting, school sources said.

Since the incident, some residents have asked Prince William police to teach a personal safety course, and the department will offer one later this month, police spokeswoman Kim Chinn said. The residents also are considering hiring a private security company.

Although neighbors have every reason to be frightened by the incident, Stokes said, she believes that it was an aberration and that the community is fundamentally safe.

"You had your problem houses here and there, but overall, people let their kids ride their bikes; they didn't even watch them," she said. "Because of the incident, people are still upset, but they are gradually coming back out again."

Staff writer Sewell Chan contributed to this report.

CAPTION: Police say Natalie Giles Davis was fatally beaten in an encounter over a car idling in the middle of the street.