A 16-year-old Upper Marlboro youth, charged with the fatal shooting Tuesday of a woman who lived next door to him, was described by several neighbors and former classmates yesterday as a withdrawn and passive person who was often taunted by his peers for his silence in school and who preferred the company of the younger children in his neighborhood.

The youth, Donald Ferrell Young Jr., was arrested in Buchanan County in southwestern Virginia late Tuesday on a warrant charging him with the slaying of Joyce Heffner, 40. He is to be returned to Maryland today.

Young had attended Frederick Douglass High School until last November and was a student at Clinton Christian School until last Thursday, when he was "asked to leave," said William Spence, principal of the Christian School. Spence declined to comment further.

William Morris, 16, a student at Frederick Douglass who said he has known Young since they were Cub Scouts together, said yesterday, "He didn't talk much at all. People would make fun of him. He was to himself. He was so afraid he would say something to get on somebody's nerves, he didn't talk to anybody."

Morris said that last year, Young was sitting in the school library reading a book about World War II when a group of students began to tease him, paging through books on the same topic and sticking some volumes in Young's face.

"He never taunted them and he never backed away," Morris said about Young. "He just stared at them with real cold eyes."

In interviews yesterday, the former classmates at Frederick Douglass also said that Young once appeared at a "spirit day" wearing what looked like a Nazi uniform. They said they had seen swastikas, the Nazi symbol, on his schoolbooks.

One neighbor, Mark Jones, 18, said he once saw Young, wearing a helmet, following him through a wooded area in their neighborhood, ducking behind trees to avoid being seen.

Young was arrested in rural Harman, Va., just a few hundred yards from the home of his grandfather, according to investigator Thomas F. Wingate of the Buchanan County sheriff's department.

At a juvenile court hearing yesterday, Young, represented by a Grundy, Va., lawyer Thomas Scott, agreed to return to Prince George's County, where he is charged with the first-degree murder in the shooting death of Heffner inside her home at 11311 Parkmont Dr. Scott declined to comment on the case yesterday.

Young was driving Heffner's cream-colored 1981 Pontiac Bonneville when he was arrested.

Inside the car police found two high-powered rifles--one in the front seat that was loaded but not ready to fire, and the second unloaded and lying in the floor of the rear of the car, Wingate said. Law enforcement officials yesterday refused to say whether either of the weapons confiscated was the rifle allegedly used in the killing.

Wingate said police also found an air gun in a case under the unloaded rifle and other items, including what appeared to be a military-style jacket.

Wingate said he recognized the car from the description provided by Prince George's police, who had issued a warrant for Young's arrest and alerted police in the Harman area that Young's grandfather lived there.

Wingate said Young appeared calm and offered no resistance when arrested.

He said that Young had asked, "What's going on?" after Wingate identified himself as a police officer. Wingate said that when he asked Young who owned the car, the youth responded, "a friend."

Heffner, a nurse who had two children, was found dead on the kitchen floor of her home about 11 a.m. Tuesday. Police said she had been shot several times with a high-powered rifle.

Prince George's police went to Heffner's home after her 5-year-old daughter, Jennifer, dialed the emergency 911 number and told police her mother was lying on the kitchen floor. Police said they are not sure whether the girl, who indicated that her mother was unconscious, had witnessed the shooting.

Although the child hung up the telephone before she gave police the address of the house, the home was located through new communications equipment that displays telephone numbers from which 911 calls are dialed.