A not so pleasant thing happened in Pleasant Valley last week.

Six days after residents lovingly installed a large welcome sign at the entrance to their idyllic Fairfax County neighborhood, someone stole it.

"It's just mean-spirited nasty," lamented Pam Cave, who helped raise the $1,900 it cost to erect the 8-by-3 1/2-foot wooden sign.

Others had harsher words for the culprit or culprits. "This was the act of a coward," Tom Hutchins said. "The sign represents the spirit of this community, and someone took it away from us."

The sign disappeared between 3 and 6 a.m. Aug. 14. Whoever took it had to unscrew 18 fasteners from two posts, leading angry Pleasant Valleyites to conclude that this was not the work of amateurs.

"Whoever did it planned it, because they needed time and proper tools," Cave said.

Hutchins added: "Normally, kids around here smash a mailbox or throw tomatoes at a car, but it's a quick, hit-and-run. This you had to spend time [on], and no kid is going to do that."

In the annals of crime, sign-stealing is hardly a novel way to start a police rap sheet. Signs get pilfered all the time, usually by college-age or teenage pranksters. A placard with "Welcome--Pleasant Valley" on it undoubtedly was a tempting target.

But that hasn't soothed the decidedly unpleasant mood among Pleasant Valley's 500 families.

"We gathered together as a community and went out and put together a phone book to raise money for that sign," groused Hutchins.

The neighborhood has vowed to fight back.

At an emergency meeting convened Monday night at the pool house, residents agreed to post a reward to get their sign back. Volunteers will canvass the neighborhood with jars to seek donations.

"We're resolved to find out who did this," said Cave, who is spearheading the drive. "I know it's a small thing in the big scheme of things, but this was something that we took pride in. We're just heartbroken over this."

NOTE TO READERS: If you just happen to have a large wooden "Welcome--Pleasant Valley" sign hidden under your bed, know this: Fairfax County police detectives have your fingerprints.