(CNN) -- Police said Tuesday that ballistic evidence had conclusively linked the fatal shooting of a woman Monday night to the Washington-area sniper attacks.

The woman was slain by a single gunshot Monday night in the parking area of a Home Depot store. She was identified as Linda Franklin, 47, of Arlington, Virginia.

The shooting makes Fairfax County, Virginia, the fifth locale in the Washington area in which the sniper has struck. Nine people have been killed and two wounded, each victim shot with a single .223-caliber bullet.

Police said they had witnesses to Monday night's shooting and were on the lookout for a cream-colored Chevrolet Astro van with the left taillight out and a silver ladder rack on top. Despite a cordon established around the area shortly after the shooting, the van has not been found.

Some witnesses got license tag numbers from a cream-colored van they saw driving around the area after the shooting, authorities said.

Fairfax Police Chief Tom Manger said the woman was shot once in the upper body and was dead at the scene. According Ellen Qualls, a spokeswoman for the Virginia Governor's Office, the victim was with her husband.

Manger said the victim had finished shopping at the Home Depot and was at her vehicle on the ground level of a two-story parking garage outside the store.

Though he would not say whether it appeared the shot was fired from a distance, as has been the case with the other shootings, Manger said: "There's no evidence of a robbery."

The shooting happened around 9:15 p.m. at the Seven Corners Center on U.S. Highway 50 in Falls Church, Manger said.

Manger said there were "several" witnesses, but he would not say whether they saw the sniper. He said investigators were still looking for the origin of the shot.

Raymond Massis, a witness, said he heard a shot as he approached the front of the Home Depot.

"People started panicking -- I was one of them. A few seconds later people started running. We heard the sirens," he said. "I looked back toward Route 50, which is about 20 to 30 yards away from me, and saw the body laying down."

Employees at the shopping center Monday said customers ran into their stores saying they heard a single shot. The one-bullet attacks have been a hallmark of the sniper case so far.

"One customer did tell us that they heard a loud bang," said Liz Cui, an employee at the Starbucks coffee shop in the shopping center. She said the parking lot was filled with investigators and police cruisers.

Police sealed off the parking lot and told reporters to move back. "We think we might have evidence in the parking lot," one police officer said at the scene.

Sniper task force rushes to scene
Police officers and investigators blanketed the area shortly after the shooting.

Authorities blocked off Interstate 495 -- the so-called "Beltway" -- and set up roadblocks along U.S. Highway 50, which leads from Virginia into Washington and connects to I-495. They also closed the George Washington Parkway, the American Legion Bridge and the Woodrow Wilson Bridge.

Officers were writing down the license plate number of every vehicle moving through the roadblocks. Police helicopters with searchlights hovered over the interstate and other nearby roads. At least one motorist was in tears as armed officers, taking no chances, searched her van -- a Chevrolet Astro like the one sought by investigators.

Police began easing the roadblocks several hours after the killing.

The sniper task force -- made up of police, FBI agents, members of the Bureau of Alcohol, Tobacco and Firearms, and the Secret Service -- converged on the scene. The Montgomery County, Maryland, Police Department is leading the investigation.

In the same shopping center as the Home Depot is a Michaels craft store. The sniper began his shooting spree on October 2 at a Michaels in Maryland but missed his intended target. The sniper wounded a woman at a Michaels two days later in Fredericksburg, Virginia.

Authorities are offering a $500,000 reward leading to the arrest and conviction of the shooter.

Discovery of rifle downplayed

Police conceal the body of Monday night's victim while investigating the scene of the shooting.

Meanwhile, the task force investigating the attacks cast doubt Monday that the discovery of a high-powered rifle, a book about snipers and other material at the Baltimore apartment of an ex-Marine was in any way connected to the shooting spree.

Baltimore police also seized a white van owned by the 37-year-old former Marine similar to one described near Friday's shooting, a department spokeswoman told CNN.

Initial tests on the gun and ammunition did not produce a match with the ballistics evidence found at the sites of the sniper attacks, law enforcement officials said.

Baltimore police went to the man's apartment after his girlfriend allegedly shot him in a domestic dispute Sunday evening. The girlfriend is in custody, a law enforcement source told CNN, and authorities said the ex-Marine agreed to be questioned further.

Investigators asked the Army and Navy to check records for any current or recently discharged sniper-trained personnel who recently have been in metro Washington. Pentagon sources said there were no military-related suspects in the sniper case.

President Bush, speaking out for the first time on the string of deadly slayings, said Monday the spree is "a form of terrorism."

"I'm just sick -- sick to my stomach -- to think that there is a cold-blooded killer at home taking innocent life," Bush said. "I weep for those who have lost their loved ones. ... Any time anybody is randomly shooting, randomly killing, randomly taking life, it's cold-blooded murder."

Although the weekend was free of attacks linked to the sniper, no more than two days have gone by without a shooting since the attacks began.

Two men were gunned down in separate Virginia incidents while they were pumping gas at filling stations near major interstates -- one killed Wednesday in Manassas and the other Friday near Fredericksburg, a brazen shooting carried out within sight of a policeman.

Five people were killed in Montgomery County on October 2 and 3. A Washington man was gunned down the night of October 3. A woman was wounded in Spotsylvania County, Virginia, on October 4, and a schoolboy was wounded October 7 outside his middle school in Bowie, Maryland.