An 8-year-old Arlington girl was molested in the bathroom of Nottingham Elementary School while she and two other children were restrained in a toilet stall by an assailant, police and school officials said yesterday.

Police said they have no suspects and are continuing an investigation. The pupils were not identified because they are minors.

Edward Reynolds, principal at the school, at 5900 Little Falls Rd., said the incident occurred about 11:45 a.m. Tuesday, the first day of school for Virginia students. He said this was the first assault of this kind that he could remember during in his seven-year tenure at the school.

He said one of the pupils had received permission from her fourth-grade teacher to go to the bathroom. The girl was absent longer than the teacher expected, and she sent two pupils to retrieve the girl.

The assailant was in the bathroom when the two pupils entered, Reynolds said, recounting the story pupils told police. The man herded them into the stall, the pupils told police. He said the pupils believed the assailant was 18 to 20 years old.

Reynolds said the man fondled one of the girls. At the same time, one of the other pupils slipped away under the walls of the stall and began screaming. The other two joined in and the assailant fled, Reynolds said.

"They followed his direction up to a point," said Reynolds. "I think you have to commend the girls, really."

Reynolds said that all three girls returned to school the following day and that a school system counselor and psychologist had visited each classroom on the ground floor, where the restroom is located, to talk to pupils about the incident.

Reynolds also sent a letter home with pupils Tuesday, explaining the incident and the steps the school system had taken in notifying police and other school officials. The letter suggests that parents let their children "discuss their fears, anxiety and concerns" and to "please reassure them that the school staff is available to discuss this with them."

Although schools grounds are open, signs are posted at every door requesting that visitors check in with the main office.

Eleven Arlington police officers are stationed in the county schools year round. Some rotate from school to school. Their main job is to develop police-youth relations, not to provide security.

"This really doesn't happen very often," said school spokeswoman Margaret Heckard.

Cindy Hicks, president of the Nottingham PTA and a parent of a pupil there, said she believed Reynolds acted appropriately in responding to the incident. She said it was a close-knit community where parents and teachers know one another, and would be aware of strangers on campus. "It was the first day when things are a little out of kilter," she said.

Floyd Hicks, her husband, said, "It's a hard thing to deal with. There's a tendency to overreact and scare people away from going to school."

Reynolds, who said he patrols the surrounding neighborhood in his car every morning as pupils are coming to school, said he has noticed a greater number of parents accompanying their children.