Woman Shot Dead in Va. Parking Lot

A woman was shot and killed tonight in Fairfax County, Va., and police are investigating the attack as though it might be the work of a sniper who has terrorized the Washington, D.C. area.

The unidentified woman was shot in upper body while she was in the parking lot of a Home Depot store in Falls Church at about 9:15 p.m. ET, said Fairfax County Chief of Police Thomas Manger

Many roads, including a portion of the freeway beltway that rings Washington, D.C., are closed as authorities search for a possible shooter. An alert has been issued for a cream-colored Chevy Astro van with a right-rear tail light out of service, Manger said.

Manger said it was "too early to tell" if the shooting was the work of the same person who has killed eight and seriously injured two others for nearly two weeks. But he added: "We are working it and investigating it with that potential in mind."

Besides the description given by Manger during a press conference outside of the shopping lot where the shooting occurred, other reports were heard on police scanners.

In one, authorities were asked to be on the lookout for an olive-skinned man wearing a blue denim jacket and blue jeans and carrying a semi-automatic rifle. In another, police were searching for a cream-colored GMC Safari van while a different report said the vehicle might be a a 1990 white Dodge Caravan.

Domestic Dispute Probed

Before the latest killing, police questioned a man who was shot during a domestic dispute over the weekend. Authorities discovered him to drive a white van and to have a number of weapons.

In the case of the man questioned, three investigators told ABCNEWS' John Miller that he came to police officers' attention when they found him wounded Saturday night in his white Astro minivan. Authorities have been on the lookout for such a van, which eyewitnesses said sped away from the scene of a shooting Friday in Virginia that left a Philadelphia man dead.

The man being questioned was shot by his girlfriend in an apparent domestic dispute, authorities said. He was treated at a Baltimore hospital.

Police found police scanners and maps in the van, sources said. Investigators also obtained a search warrant for the man's Baltimore apartment and allegedly found a Marine Corps sniper's manual and other books on snipers, police scanners and an arsenal of weapons that included an AR-15 and five handguns.

Police test-fired the AR-15 but it didn't match the one used by the sniper. Police believe the potential suspect has another AR-15 that they have not found yet. None of the weapons found in the man's home match the ballistics evidence recovered in the shootings but sources told ABCNEWS that police are searching for additional weapons at another location.

The man, who was not identified, is a former eight-year veteran of the Marines with no criminal record, sources said. He works as a radio repairman for Motorola. Baltimore police began questioning him this afternoon.

Sources told ABCNEWS that investigators are also interested in at least three other potential suspects. All three have had emotional problems, have access to white trucks and are known for collecting firearms, the sources said. Investigators learned about these other suspects through tips phoned in from associates who were concerned about them.

Police Report Progress, Little Else

Under pressure from the worried public, police have been trying to find the sniper responsible for a series of shootings that have terrified residents of Washington, D.C., Virginia and Maryland since Oct. 2 . They have released images of a white panel truck, the kind used for deliveries, that witnesses say may have been linked to some of the shootings. They were also expected to release a composite photo of the white Astro van.

Jittery residents braced themselves for another sniper attack today, even though there has not been an attack since Friday — the longest break by the sniper yet. Earlier today, police insisted they were making progress in the case but refused to share detailed information with the public.

"I think the progress is going very well," said Montgomery County, Md., police Chief Charles Moose. "Certainly some of you may deem me an optimist."

Moose said today that witnesses at several incidents reported seeing the white box truck that may be connected to the shooter.

And they are also looking at surveillance videos. They interviewed at least one man who was near the site of the latest confirmed shooting, which occurred Friday at a gas station in Spotsylvania County, Va., about 50 miles south of Washington. The man told The Associated Press that detectives thought at first he was the shooter, after comparing him to a sandy-haired man who was seen on the tape.

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Communities on Edge, a President Sickened

Across the Washington area, there are signs life has changed. Drivers gassing up their cars have been seen crouching behind the pumps, or asking members of the Guardian Angels volunteer organization to fill the tank for them. One driver was even wearing a bulletproof vest.

"I'm just doing what I feel is safe for me until they catch him," said Harrison Scurry, of Rockville, Md.

High school football practice moved indoors, and tailgate parties for a Sunday Redskins game were held under the watchful eyes of police chaperones.

"I'm more aware of our surroundings and, you know, we basically didn't want to park near the woods," said local resident Andy Keninitz.

The sniper killings and the idea that people were living in fear revolted President Bush, who made his first on-air comment about the attacks.

"I'm just sick — sick to my stomach — to think that there is a cold-blooded killer at home taking innocent life," Bush said. "The idea of moms taking their kids to school and sheltering them from a potential sniper attack is not the America that I know."

Police have been flooded with tips from worried residents. Many of the tips have been false alarms, Moose said.

"We also want to admit that people are edgy," he said. "People are hearing things."

Tracking a Killer

Investigators have noted a number of other patterns: the killer favors suburban gas stations; fires a single round; has not let two weekdays pass without opening fire again; and, judging from a tarot card found at one crime scene, appears to enjoy taunting police.

According to sources close to the investigation, the Pentagon has been asked to search records for recently discharged GIs who have had sniper training.

However, police are not commenting on the reports. Nor are they talking about a yellow piece of paper found at the scene of Friday's killing in Virginia. It reportedly contained scribbled directions from northern Maryland to the Capital Beltway, the highway that rings Washington, linking Maryland and Virginia.

The release of the composite image and the timing of the sniper shootings has led to speculation that the sniper may be a contractor who has access to these white trucks through his job but is off weekends when he doesn't have access. One theory is he is shooting from inside the back of the truck.

Some suspect the sniper chooses locations that offer a quick getaway. The last four shootings were all close to major highways and quick escape routes.

Police have also used computer software to reconstruct the crime scenes and pinpoint the shooter's position. Originally designed for movies like Star Wars, the programs can line up the bullet trajectories.

Authorities today offered an address for people to send in tips: P.O. Box 7875, Gaithersburg, MD 20898-7857. People who want to report information on the case can also call a tip line set up by police: 1-888-324-9800.

So far, authorities say they have received more than 1,700 credible leads since the shootings began. The reward for any information leading to the arrest and indictment of the individual or individuals responsible for the shootings has now reached $500,000.

Contributions to the reward can be sent to Montgomery County Reward Fund, Office of the County Executive, 101 Monroe St., Rockville, Md., 28050. Contributions also can be made by telephoning (240) 777-8970.

ABCNEWS' John Miller in Maryland and Pierre Thomas in Washington, D.C. contributed to this report.