Rockville, Md. ? People who saw the Washington-area sniper aim, open fire and flee in a white van were not able to give investigators enough details to create a composite sketch, police said Wednesday.

It was the latest setback in the hunt for the gunman who has killed nine people in two weeks.

“Unfortunately, distance and darkness, and perhaps adrenaline, have made them unable to give a clear composite that we can disseminate,” Montgomery County Police Capt. Nancy Demme said. “I know that’s not what the public wants to hear.”

Investigators said Monday night’s shooting of 47-year-old FBI analyst Linda Franklin outside a Falls Church, Va., Home Depot store was the first time witnesses saw an actual shooting rather than just shadowy figures fleeing.

More than one bystander reported seeing the shooter, but their descriptions were not consistent, investigators said. The gunman was variously described as dark-skinned, olive-skinned, Middle Eastern and Hispanic.

“The only common denominator thus far is male,” Demme said. “We don’t have a refined description to go by.”

James Parson Sr. of McLean, Va., raises his hand in salute to the ninth victim of the Washington-area sniper, at the site where Linda Franklin was gunned down in Falls Church, Va. Although many witnesses were nearby when the shooting occurred Monday, none could give a good description of the sniper.

Demme gave a “how-to” list of tips for potential witnesses in case the sniper strikes again. Among them: Stare in the direction of the bullet noise, carry around a pen to take notes and, if necessary, write down details on your hand. She also warned witnesses not to “contaminate” their memories by comparing notes with other people or the media.

After the latest shooting, witnesses for the first time were able to give information about license plates on vehicles they said fled the scene.

The numbers have not been released. Montgomery County Police Chief Charles Moose said the numbers were partials, “and we don’t put out partials.”

Since Oct. 2, there have been 11 shootings in Maryland, Virginia and Washington that have left nine people dead and two wounded. The victims were cut down by a single bullet as they went about their everyday activities.

A tarot death card left at one scene read: Dear Mister Policeman, I am God.”

¢ www.co.mo.md.us¢ www.fbi.gov