FALLS CHURCH, Va. -- An FBI terrorism analyst was identified Tuesday as the ninth person killed by the Washington-area sniper, shot in the head in an attack investigators say has yielded the most detailed clues yet.

For the first time, witnesses were able to give information about license plates on vehicles seen fleeing the scene, including a light-colored Chevrolet Astro van with a burned-out rear taillight.

A law enforcement official, speaking on condition of anonymity, said another witness gave a description of a dark-skinned man, possibly Hispanic or Middle Eastern, in a white van.

"There was some additional information that we were able to get from last night's case, and I am confident that that information is going to lead us to an arrest in the case," Fairfax County Police Chief Tom Manger said.

Law enforcement sources said there was no indication the sniper targeted Linda Franklin because of her job. She worked for the FBI's Cyber-Crimes Division, created last year to focus on computer crimes as well as intellectual property cases.

Montgomery County, Md., police chief Charles Moose, the head of the investigation, emphasized that Franklin was not working on the sniper case.

Franklin, a 47-year-old mother of two grown children, was killed Monday night as she and her husband loaded packages into their car outside a Home Depot store.

Ballistics evidence Tuesday connected the slaying to the gunman who has killed eight other people and wounded two more since Oct. 2.

With the terrifying spree nearly two weeks old, Defense Secretary Donald H. Rumsfeld agreed Tuesday evening to provide military surveillance aircraft in the hunt for the killer, a Pentagon spokesman said. Sources said federal agents on the plane will relay any information they collect to authorities on the ground.

The Army also has started searching its records for people with sniper training.

Separately, Homeland Security Director Tom Ridge said investigators are hesitant to rule out the possibility that the slayings are the work of a terrorist because there is no hard evidence about motive.

Plans to move

Friends who gathered at Franklin's Arlington home said she and her husband were planning to move to a bigger home in the area and were at The Home Depot to buy supplies for the move and the new house.

Franklin recently had a double mastectomy following breast cancer and was still in physical therapy at the time of her death, according to her friend Paul Hulseberg. He called her courageous.

"Linda was a dedicated employee, and she will be missed," FBI Director Robert Mueller said. "All of us are deeply shocked and angry over this tragedy."

Robert Young, a Washington construction worker, returned to the shopping center Tuesday to talk with police. He said he had heard a gunshot and saw a white van the night before.

Young said as he backed his truck out of his parking spot, a white Astro van with two men inside tried to turn into his lane. He said the driver appeared very agitated to find his way blocked and instead drove by a neighboring Chinese restaurant and out of sight.

Young described the driver as a short man of slight build who appeared to be Mideastern. He said, "I got a good look at the guy."

The driver "seemed to be excessively irritated because he couldn't pull into my lane," he said. "I thought this fool was going to want to get out of the van and duke or something. But he didn't. He kept on going."

In a continuing appeal for the public's help, Moose released composite images of a white van with roof racks that witnesses saw after Friday's slaying of a man at a gas station near Fredericksburg, Va.

Moose said there appeared to be similarities between the van seen at Friday's shooting and the van from Monday night's attack.