MASSAPONAX (USA), Oct 11: Police launched a manhunt on Friday after another fatal shooting in a gas station near Washington, heightening public fears after seven killings by a sniper.

A man was shot and killed at an Exxon station in Massaponax, Virginia, 80kms south of Washington, police said.

Police did not immediately link the killing to the previous sniper deaths, but they launched a major security operation in Virginia.

Huge traffic jams built up on Interstate 95, the main highway along the US East Coast, as police checked scores of vehicles. All exits in Northern Virginia were closed, media reports said, as police searched for a white Chevrolet Astro-type van seen in the area.

Howard Smith, a Spotsylvania County sheriff’s department spokesman, said police and federal investigators were looking at the evidence linking the killing and the sniper attacks.

He said a Virginia state police trooper was “directly across the street” working at a traffic accident when he heard one shot and went to the stricken man.

The security operation was launched after witnesses reported seeing a white van near the gas station and police said they were searching roads throughout the region.

Three of the sniper’s other victims have been killed at gas stations. Two people have also been wounded since the attacks started on Oct 2.

Police in Maryland, meanwhile, said the Federal Bureau of Investigation was to release a “graphic aid” on the sniper case later in the day, without giving further details.

Moose also made a renewed appeal for anyone who was in the vicinity of any of the nine attacks to call a central tip line.

“We certainly would like to talk to you,” Moose said. “Let us decide whether or not what you saw, what you heard, has something to do with the investigation.”

“Again, you may not have known that you were in the area of the crime scene,” he said. “We just want to talk to you so that we can do everything in our power to get the person or the people involved in these terrible crimes into custody.”

Schools near the shooting sites have stopped children from going outside and have cancelled sports activities, while some stores have reported slower business since the attacks started.

All of the victims were carrying out day-to-day activities in the Washington area, such as going to the supermarket or gassing up their cars, at the time they were shot.

Five people were killed within a 16-hour period from late October 2 to October 3 in Montgomery County, which borders Washington. A sixth person was shot in the chest and killed late October 3 while standing on a Washington street corner close to the Maryland border.

On October 4, a woman was shot in the back in the parking lot of a shopping mall in Fredericksburg, but survived.

A 13-year-old boy was shot in Bowie, Maryland, after being dropped off at school Monday and remains hospitalized, while a 53-year-old man was shot and killed late Wednesday while getting gas in Virginia.—AFP