The news out of Prince William in the past few months has been mostly rosy: America Online Inc. announced plans to build a $520 million data center outside Manassas; county supervisors approved a series of modest tax cuts; and an influx of pricey new homes led an apparent turnaround in property values.

Then came last week.

On Tuesday, 25-year-old Natalie Giles Davis was fatally beaten after a dispute with two teenage girls in Woodbridge. Early the next day, police said, 32-year-old Joseph Scott Williams died after being beaten inside a Dale City town house, dragged outside and set afire.

The savagery of the two crimes has shocked neighbors and community leaders and has once again put Prince William in a spotlight of negative publicity. The killings evoked memories of earlier crimes that landed the county in the headlines, such as the notorious case of Lorena Bobbitt in 1993, the shooting of two Neighborhood Watch volunteers in 1997 and the fatal attack on two teenage sisters in their home by an acquaintance in January.

Community leaders, while horrified by the latest crimes, say that residents and outsiders alike should remember that Prince William's crime rate is lower than many of its neighbors -- and is on the decline.

"I don't want to make light of these very serious crimes, but you have to look at them as isolated incidents," said supervisors Chairman Kathleen K. Seefeldt (D). "We're not having a crime wave. In fact, crime is down."

Local leaders report an outpouring of sympathy, and perhaps fear, among residents shocked by the slayings. Some public officials and political candidates also said the crimes underscore the need for beefed-up police presence and a greater involvement by residents in anti-crime programs.

Longtime Sen. Charles J. Colgan (D-29th District) said Prince William residents aren't used to hearing about these kinds of crimes in their own neighborhoods.

"I think everybody's just really depressed about this," Colgan said. "It's unusual for a community like Prince William to have to deal with that, especially two such incredibly vicious crimes. We like to think we're above this sort of thing. I hope it's not a trend."

Both killings occurred in the 51st House District represented by Del. Michele B. McQuigg (R), who also was the Occoquan District supervisor two years ago when the two watch patrol members were shot in Lake Ridge. In that case, she said, rallying the neighborhood was vital to calming fears and regaining a sense of control.

"Some people are probably going to be afraid," McQuigg said. "People do have to be cautious. . . . But this could happen anyplace. It's tragic that they happened here, and that they happened right on top of each other."

Commonwealth's Attorney Paul Ebert warned that, "to some degrees, it's an anomaly, but we're seeing more violence by younger people, and we're seeing more violence by young women."

Sean Connaughton, a Republican attorney from Triangle vying to unseat Seefeldt in the November elections, said the county must react swiftly to what could be a burgeoning violent-crime problem on Prince William's urban eastern end. He said the county needs to hire more police and move additional officers from desk jobs to the street.

"We have to jump on these things early before, number one, we get a reputation, and number two, it inspires other people to do the same," Connaughton said.

"There are certain areas that are under stress in the county, and more attention has to be paid to those areas on a day-to-day basis."

But Seefeldt pointed out that two suspects in the beating of Davis, who died Wednesday, were arrested immediately after the assault because an officer was nearby. A 28-year-old woman and a 17-year-old youth also were arrested in the slaying of Williams, who was mentally disabled.

Supervisor John D. Jenkins (D-Neabsco) said many of his constituents are outraged by the brutality of both killings, but most do not expect to see more of the same.

"We just don't have a history of this kind of violence," Jenkins said. "It's one of those one-in-a-million things. This could happen anywhere at any time. Everyone's just sorry it happened at all."