Police around the region raced against time all weekend to stop a seemingly insatiable killer before he can strike again.

He hit three times last week--Monday, Wednesday and Friday--leaving two dead and one wounded.

In Spotsylvania County, the scene of the latest deadly shooting, a local task force interviewed potential witnesses and chased thousands of telephone tips from frightened residents.

"We are still in dire need of the public's help," Spotsylvania sheriff's Maj. Howard Smith said. "I firmly believe that information from the public will be his downfall."

Police in Montgomery County, Md., where the gunman began his killing spree Oct. 2, said they were flooded with calls to their tip line yesterday after Saturday's release of a composite drawing of a white box truck noticed by witnesses at several shooting scenes.

Detectives last night were still working on a composite of a white Chevrolet Astro van reported by witnesses after Friday morning's brazen shooting at Four-Mile Fork Exxon on U.S. 1.

The sniper killed Kenneth Bridges, 53, as he filled his tank about 9:35 a.m. A state trooper was working a fender-bender about 50 yards away.

He heard the gunshot and saw the Philadelphia businessman and father of six slump to the ground--but caught no glimpse of the gunman.

"I think he's feeling invulnerable about now," retired FBI profiler and Spotsylvania resident Gregg Mc-Crary said of the sniper. "He feels he's smarter than the rest of us, he can elude us, he can evade us."

Experts in criminal behavior agree that the sniper is thriving on the attention he's getting from the media and the fear now gripping the Washington area.

"This is a guy who is obviously very angry and emotionally unstable," said McCrary, who was having breakfast at a nearby restaurant when the gunman hit Friday morning.

"He's reacting to the things he sees about himself on the news shows day and night. He's fueled by it. And he's angered when someone calls him a coward on the news. The media has been doing some reckless things with this story. This is not a guy we want to [tick] off by calling him names."

McCrary said he knew the sharpshooter had struck again when police cruisers went screaming by the restaurant Friday.