A 48-year-old woman was found slain, lying face down in a pool of blood, yesterday in her home in an expensive Reston neighborhood, Fairfax County police said.

The body of Constance Mason Hiner was discovered by her husband, Bob Hiner, about noon when he returned to the house in the 1600 block of Woodstock Lane for lunch, police said.

The death provoked expressions of shock and dismay from neighbors in the elegant Woodstock Lane cluster, which they said has been free of crime.

Police also viewed the incident as rare. "This is an upscale neighborhood," said Officer Onzy Elam, a spokesman. Though not unheard of, he said, homicide in such surroundings "would be very unusual."

The woman's partly clothed body was found in one of the bedrooms of the skylighted beige wooden house with white trim near Reston Parkway and Baron Cameron Avenue.

Police did not say how the woman was killed but said an autopsy is scheduled for today. A police spokesman said a weapon that might have been used was found at the scene, but he declined to give details. Another officer said it appeared that the woman had not been shot.

Elam said officers were pursuing a strong lead but declined to describe it. Police said they could not tell immediately whether there had been a forced entry. They said it was not immediately clear whether anything had been taken; the woman's car was in the garage, they said.

According to neighbors, Bob Hiner works for a Reston area property management firm and the couple moved to Woodstock Lane perhaps a year ago.

Neighbors said Constance Hiner traveled frequently, and police said she was preparing to make an airplane trip yesterday morning. Luggage was found in the house, a police spokesman said.

Neighbors said they saw the husband leave the house about 7 a.m. in his Mercedes, and one neighbor said a cab came to the house about 8:15 a.m. to pick up the wife. The neighbor, Dick Burgett, said that the driver apparently tried to telephone the woman but that she never emerged from the house.

Residents of the cluster of contemporary houses said the couple were quiet and appeared responsible, and said they knew little else about them.

One neighbor, E.A. Ward, a nurse whose husband called her at work about the death, said: "I really didn't want to come home tonight to face it. We're all so concerned."

She said that like several other neighbors, she already had a dog and a burglar alarm. "What else can you do?" she asked.

Steven Piguet, another cluster resident, said: "We don't want to find out that it was a random breaking and entering and someone got killed. That's everyone's fear."