In just five months this year, Spotsylvania County authorities have investigated four slayings, matching the county's unusually high homicide toll for all of last year.

As the gut-wrenching shock over the deaths of young Kati and Kristin Lisk turns to a nagging ache, area residents and officials face the unsettling idea that abductions and killings aren't as uncommon as they once were in the Fredericksburg area.

"We definitely have a trend with the upward numbers," Spotsylvania Commonwealth's Attorney William Neely said yesterday. "We have never, ever had this many murder cases open at the same time in the 15 years I've been here."

Normally, Spotsylvania has two, maybe three, homicides in a year, Neely said. The cases typically involve domestic partners or acquaintances whose disputes turn into bloodshed. That's what allegedly happened in two of this year's slayings.

Now the Sheriff's Office has to cope with cases that apparently involve men who prey upon young girls such as the Lisks or Sofia Silva, the 16-year-old Courtland High School student who disappeared from her front porch and was found dead late last year.

County authorities hope the four slayings so far this year, on the heels of four during 1996, are not signs of more mayhem to come.

With 23 homicides since 1990, Spotsylvania has had well more than any other area locality, according to crime statistics from local and federal sources.

Stafford County and Fredericksburg have each had 11 slayings during the same period.

Why does fast-growing Spotsylvania have better than a third of the 60 slayings in the region so far in the '90s?

Neely has no easy answer.

"We're as baffled as anyone. I don't know if it's our proximity to the interstate or the size of our population," he said. "My personal feeling is it's our proximity to 95 as much as anything."

Capt. Charles Jett, spokesman for the Stafford Sheriff's Office, said growth and the area's location between Washington and Richmond have changed the nature of crime here. The population of the five area localities has increased from about 170,000 to 216,000 in the '90s.

Still, the region's murder rate hasn't risen dramatically. It has bounced from year to year from a low of five in 1990 to highs of 11 in 1992 and 1996.

Stafford's rate has fluctuated as well. The county had four homicides last year and none so far this year.

The cases in Stafford haven't riveted public attention on violent crime the way the Lisk and Silva cases have. Still, Jett said, Stafford residents have responded by being more cautious with their children.

"People need to understand that though we don't live in a metropolitan area, we aren't immune to crime that occurs in metropolitan areas," he said.

Capt. Steve Dempsey of the King George County Sheriff's Office agreed. "Our area is changing and changing fast. When you have more people, there's more chance for crime."

Though King George is still mostly rural, he said, the region's growth has affected communities.

"I don't think there's any magic number. Any area can fall victim to violent crime."

Residents should educate themselves and their children to be aware of potential dangers around them, he said.

Neely said residents should "stay calm and be good neighbors" by looking out for one another.

Despite the slayings, he said: "It's still the same good community it's been."