Two sexual assaults on small children in the same Reston neighborhood in recent weeks have police and residents worried that a sexual predator is prowling the community.

Both victims were 5-year-old boys who were playing near their homes in the 1600 block of Becontree Lane, in the Cedar Ridge Apartments area.

About 6 p.m. Wednesday, a boy who was playing in the foyer of his building was approached by a man walking a bicycle, Fairfax County police said. The boy told police the man lured him into the nearby woods, hit him several times, then tried to sexually assault him.

A passerby walking on a nearby path saw the two, and the man fled. But the descriptions the boy and the witness gave police were similar to the description of an attacker in a Sept. 19 incident, also in the woods near Cedar Ridge.

In that incident, several children were playing outside about 5:30 p.m. when their ball rolled into the woods. A 5-year-old boy went to retrieve the ball but didn't return for about 20 minutes, Fairfax police Lt. Amy Lubas said. The boy later reported to police that he had been assaulted by a man.

The two assaults follow a series of crimes in the area. There have been five sexual attacks on women in Reston over the past year, the first of which was just blocks away from the Cedar Ridge complex.

Two people have been slain in separate shootings in Cedar Ridge in the past 14 months. One man has been convicted in the first shooting, and another man awaits trial in the second.

The series of crimes has increased anxiety in the north Reston neighborhood. Turnout at community meetings is up and there is more participation in anti-crime programs, said Capt. Bob Beach of the Reston police district. After the second homicide in February, Beach said, police met with the management of Cedar Ridge, and a community crime watch group was formed.

"I felt we were making great results," Beach said with frustration. He said criminals may be invading the neighborhood from elsewhere, and he praised residents for not panicking.

Cedar Ridge is adjacent to Forest Edge Elementary School, where teachers and staff members met yesterday afternoon to discuss how to broach the subject with children in class today. Principal Frank Bensinger sent a letter home with students laying out the facts of the latest incident and suggesting that parents review safety procedures with their children. A crisis team of psychologists and social workers also will be available at the school today, school district spokeswoman Kitty Porterfield said.

The suspect is described as a black man, 5 feet 9 inches to 6 feet tall, weighing 150 to 190 pounds, with a thin mustache, wearing blue running pants and a green jacket, and pushing a black-and-silver mountain bike. Anyone with information about the assaults may call the Fairfax County police sex crimes unit at 703-246-4623.