A man was shot and seriously wounded at a gas station Friday, and police searching for a sniper closed down a nearby interstate after reports that a white van had been seen in the area at the time.
It wasn't immediately clear if the shooting near Fredericksburg was linked to nine other attacks that have left seven people dead in the Washington area.
Spotsylvania County Sheriff Ronald Knight said authorities had pulled over several white vans on Interstate 95 after the 9:30 a.m. shooting and had reports of a white van bumping other vehicles, apparently trying to get out of the area.
Authorities had one van surrounded near Alexandria, about 40 miles away.
``We're being very cautious at this time,'' Alexandria police Lt. John Crawford said. He said police had stopped a ``white panel truck'' and were waiting for help from Fairfax County police before approaching it.
A white van or box truck had also been spotted near the scenes of two other shootings linked to the sniper. One van was pulled over shortly after a fatal shooting Wednesday night in Manassas, but the occupants had a reasonable explanation for being in the area, Prince William County Police Chief Charlie Deane said.
The shooting Friday morning at an Exxon station near Fredericksburg seriously wounded one man, Gov. Mark Warner said. The victim's condition wasn't immediately available.
There have been no known witnesses to the sniper attacks that started more than a week ago in suburban Washington; however, police have been reviewing video surveillance tapes from the shooting scenes, all public places.
Friday morning, Montgomery County, Md., Police Chief Charles Moose said a special projects unit of the FBI was working ``with a sense of urgency'' on a graphic aid to be distributed to the public in the search for the sniper.
He and FBI officials declined to describe the graphic, but said it would be clear later Friday.
Authorities haven't said if tapes from Wednesday night's attack, at a gas station in Manassas, held any clues.
A 53-year-old civil engineer traveling from his job in Virginia to his home in Gaithersburg, Md., was killed after pumping gas just off Interstate 66.
Like the other victims, Dean Meyers was felled by a single shot from a high-power rifle. Police said ballistic evidence linked Meyers' death to the sniper.
``This is crazy. It's too close to home,'' Michelle Rhoades, 19, of Triangle said Thursday night as she stopped at a gas station in Woodbridge, about 15 minutes from where Meyers was killed.
She said she didn't want to live in fear but admitted she had been scanning the area around her for any place a sniper might hide.
Meyers' death in Prince William County broadened the scope of an investigation that has frightened residents in suburbs surrounding the nation's capital and has strained police in two states and the District of Columbia.
The shootings, including one Monday that critically wounded a 13-year-old boy outside his school in Bowie, Md., have led schools across the region to cancel field trips and outdoor activities during the week.
Last weekend was free of attacks, but Moose said he isn't willing to bank on another lull.
``We know that it's the weekend. There won't been any rush hour, there won't be any school, but there will be events and certainly we're aware of that,'' he said.
Residents, meanwhile, have been modifying their shopping habits to avoid putting themselves in danger.
Bebi Tasawar, the mother of three working in a glass-fronted 7-Eleven, said she was afraid to come to work knowing the sniper had been within 10 miles of her store. It didn't help, she said, that the parking lot was unlit and that the store is adjacent to thick woods.
``When we throw the trash out, we're looking around. It's scary,'' she said. ``You don't know when you walk out the door what will happen next. He could be watching us right now.''
Just across the parking lot, Robert Evans was working security at a Sheetz gas station and convenience store. The station normally only has security guards on weekends, but he was brought in for an 8 p.m to 6 a.m. shift.
``I'm paying a lot more attention to the tree line,'' he said.
While pumping gas, Jerry Hughes continually shuffled around his car.
``I figure he's shooting at targets that are not moving, so if he wants to keep shooting at gas stations, I'll keep moving until my gas is pumped,'' the 42-year-old Hughes said.
A toll-free hot line set up to accept tips was overwhelmed by calls Thursday. Police were advising callers getting busy signals to keep calling. Additional phone lines were being installed.
Still, police were deliberately vague about their evidence and leads.
``It's a difficult case but we are developing more information as the minutes go by,'' Deane said Thursday.
Manassas is about 35 miles southwest of the Maryland suburbs where most of the attacks happened. Meyers' shooting was the second in Virginia. A woman was wounded by the sniper last Friday in Fredericksburg, 30 miles south of Manassas.
Police in yellow slickers walked shoulder to shoulder Thursday through a drizzling rain, looking for evidence near where Meyers was shot. Deane did not say whether they had found anything, but said there had been no communication from the killer.
At the site of Monday's shooting, police found a tarot death card with the taunting words, ``Dear policeman, I am God'' near a bullet shell.