A fatal shooting during the weekend brought to 12 the number of homicides in Arlington in 1990, a record for the county, according to police officials.

The most recent homicide occurred early Sunday, police said. Responding to reports of gunfire, officers found Gregory Bigsby, 32, of South Lincoln Street, lying on the pavement in the 2400 block of Shirlington Road.

Bigsby was taken to National Hospital for Orthopaedics and Rehabilitation, where he was pronounced dead at 7:45 a.m. No arrests have been made in the case.

Less than a week ago, a South Arlington man was shot to death in the county's 11th slaying. Police have charged his onetime girlfriend, Thelma D. Rainey, of Alexandria, with murder.

Arlington County has seen killings of unusual brutality as well as number this year, police said. Last spring's stabbing of Anne Elizabeth Borghesani, 23, a Washington paralegal, shocked Arlingtonians into altering their use of the county's recreational trails.

Borghesani was stabbed repeatedly on March 31 while walking along the trail from her apartment to the Rosslyn Metro station. Michael Charles Satcher, of Washington, has been arrested and charged with first-degree murder in the killing.

While the latest killings cap an unusually violent year in Arlington, the circumstances in many of the cases "have also been unusual," said Lt. Kenneth Madden, who heads the police department's homicide unit.

In at least three cases, Madden said, the killings resulted from domestic disputes. In the case of Chander Matta, Madden said, "one man has been charged with three, that's the first time that has ever happened in Arlington."

Matta, 22, has been charged in the asphyxiation deaths of three women over Memorial Day weekend.

Excluding those cases, Madden said, brings the number of homicides "down to a number more in line with what we have had in the past."

"It's unusual to have as many as we have this year, but it was unusual to have as few as we had last year," Madden added.

In 1989, there was one homicide in Arlington.

John Robinson, director of the Martin Luther Community Center, which is near the site of Sunday's shooting, said he had spent part of Saturday afternoon counseling Bigsby "to get his life together."

Robinson said Bigsby had "problems with the law" off and on throughout his life.

Bigsby had come by the community center again about 2 a.m Sunday morning, Robinson said, looking for a place to spend the night. "I said, 'You have to come back in the morning,' " Robinson said. "I feel kind of guilty about it now, but there's nothing I could have done, really."

Shirlington Road, the strip of South Arlington where Sunday's shooting occurred, forms the heart of the county's drug corridor. The area also has been the site of nightly patrols by citizens trying to eradicate drugs from their community.

Police said they have not determined whether Sunday's shooting was drug-related.

"It's really depressing," said Joan Cooper, a community activist and longtime resident of the Nauck community, where the shooting occurred. "That whole corner is a sad, sad sight."

On the night of the most recent shooting, Cooper said, the corner of 24th and Shirlington roads, usually bustling with activity, was quiet, its regulars apparently frightened away by news of the shooting.

"I've never seen it so dead," Cooper said. The shooting "might be a blessing in disguise."