Investigators say ballistics tests prove that the sniper terrorizing the Washington region was back in Spotsylvania County yesterday, killing a father of six at a Spotsylvania County gas station.

This time, the brazen killer struck within 50 yards of a uniformed state trooper.

Authorities assumed from the start that they were dealing with the gunman who had already shot nine people, killing seven.

"Who else could it be?" one local investigator said yesterday.

Authorities plan to announce details today, now that the Bureau of Alcohol, Tobacco and Firearms has performed ballistics tests on bullet fragments from the victim's body.

"I think what we've collected will give us some answers," Spotsylvania sheriff's Maj. Howard Smith said last night.

Kenneth Bridges, 53, of Philadelphia was pumping gas at the Four-Mile Fork Exxon station about 9:35 a.m. when he was felled by a single gunshot to the upper body. He becomes the eighth person fatally wounded by the unknown sniper in the Washington area in the past nine days.

Bridges was a graduate of the University of Pennsylvania and was co-founder of a marketing distribution company.

"The family and friends are understandably shocked and saddened by this senseless event," Gary Shepherd, a family friend, told reporters in Bridges' neighborhood in northwest Philadelphia.

The spree killer has left only two survivors in his nine-day rampage around the Washington area. On Oct. 4, a 43-year-old Spotsylvania woman was shot in the back outside Michaels Arts & Crafts near Spotsylvania Mall, exactly one week before yesterday's shooting. She was released from the hospital Tuesday.

On Monday, a 13-year-old boy was critically wounded as he walked into school in Bowie, Md. He remained in critical but stable condition yesterday at Children's Hospital.

All of the earlier victims were shot with a .223-caliber round, which is popular with police, the military and hunters for its accuracy and deadliness.

Authorities weren't discussing last night what type of bullet killed the Philadelphia man or where it came from.

Investigators combing the area as a rain fell off and on throughout the day did recover some evidence at the scene of the Exxon shooting, but not a shell casing. Casings were found at two other shootings--the attack at the Spotsylvania Michaels and the shooting outside the Bowie middle school.