Timothy Joseph Buzbee, who grew up in the well-to-do Flower Valley section of Aspen Hill, was formally charged yesterday with two counts of rape, but residents of the Montgomery County community that has been terrorized by 16 sexual assaults in the last 18 months said they were still fearful.

"My fear is it's a lot like Tylenol and there will be copycatting," said one Aspen Hill woman who has a 13-year-old handicapped daughter. "I have the lights on all the time and I'm going to get the bushes in my front yard cut. We're pretty much living like prisoners, with windows nailed and doors double-bolted . . . I'm going to feel a little sense of relief, but I'm not going to change my precautions."

Aspen Hill residents who knew the 25-year-old Buzbee, a real estate surveyor, and neighbors who now live near him, his wife and two children in the well-kept Fredericktowne Village subdivision in Frederick, Md., said they were shocked and mystified at the arrest.

"We saw them almost every day," said Mike Lyons, who said he met the Buzbees two years ago in their new community of $70,000 ranch and split-level homes. "During the summer we had block parties in front of their house. He was good on Halloween. He stayed in the house and handed out candy while his wife took the kids around trick or treating."

Buzbee, who is being held without bond at the Montgomery County Detention Center, is charged with two counts each of first-degree rape and robbery, and one count each of trespassing, nighttime burglary and assault and battery, court and police officials said.

Police said Buzbee had no police record and that the robbery and assault and battery charges allegedly involved an incident that occurred in Silver Spring in 1980. The attacks in Aspen Hill began in March 1981, with the most recent occurring Oct. 2. Police have said he is charged with rape in connection with an attack that took place in July 1981. Montgomery County police said they have information linking him to other sexual assaults in the area.

He is scheduled to appear before a District Court judge at 8:45 a.m. tomorrow for a bond review hearing.

Police said there were 16 sexual assaults in the Aspen Hill area that they believe were committed by the same individual. The attacks, on girls and women aged 11 to 38, changed the usually tranquil lives of Aspen Hill residents.

"I have a wife and little sisters I've been scared to death about," said a 24-year-old man who lives only yards from the site of one assault. He said the rapes caused him to teach his wife to shoot a .45 automatic pistol, which is kept by their bed. "Now we have to worry about the judicial system giving him a $100 fine and sending him on his way," if he is found guilty.

Lyons said Buzbee had left surveying to take part-time work as a salesman at a lumber yard earlier this year when the real estate market declined. Lyons said Buzbee also had a few other part-time jobs and that Buzbee had recently returned to his surveying work in Gaithersburg.

"He seemed to be an all-around family man," said another Fredericktowne neighbor, Bruno Nicknadarvich. "He helped me with my rec room and I helped him with his."

News of the arrest did not diminish some Aspen Hill residents' anger at the way police had handled the series of sexual assaults. Lois Barrett, who is one of the many area residents who knew one of the victims, complained that the police did not alert residents soon enough to the fact a number of rapes were occurring in their neighborhood.

Buzbee, a graduate of Good Counsel High School, a Catholic boys school in Wheaton, grew up less than a half-mile from where several victims were raped.

Police arrested Buzbee Friday evening.