Eric James Long, 36, was a popular figure among the children at his Silver Spring town house development. He had a bike, a beagle, a hamster, video games, Frisbees, footballs and a motor scooter. He was equally well liked at a private Bethesda school where he had worked as a gymnastics instructor since 1978.

Last month, the parents of Long's young friends, as well as his employer, were shocked to learn that he had been arrested and charged with sexual offenses against six boys in his neighborhood, ages 6 to 11. And then they learned that Long had been convicted twice previously of molesting young boys, but never spent any time in jail. He has not yet entered a plea on the recent charges.

"It seems incredible to me that this man could do these things to . . . children and not have anything triggered to send him to jail," said the mother of an 8-year-old boy who was the first child to accuse Long in this round of charges.

Parents and school officials blame the current judicial system for making it difficult to track convicted child molesters, and they are backing a new law that has been adopted in about 10 states that would require schools and day-care centers to run criminal checks on persons seeking jobs. Similar bills are under consideration in a dozen other states, including Maryland and Virginia.

In 1972, Long was arrested in Maryland and convicted of sexually assaulting a boy. But when Long was hired in 1978 as a part-time gymnastics instructor at the French International School in Bethesda, school authorities had no way of knowing about his conviction. Schools and other facilities that care for children are not required to run criminal background checks, nor is the information readily available.

He was arrested again in 1979 and was convicted in 1980 of sexually molesting one of the boys he coached in soccer for the Montgomery County Recreation Department. The private school authorities said recently they did not know of his convictions, even though he was working for the school at the time.

For both of his earlier convictions, Long was given three years probation on the condition that he receive psychiatric treatment.

Concern over sexual abuse of children has triggered reaction on several fronts. For example, a bill backed by Gov. Harry Hughes was introduced last Thursday in the Maryland General Assembly that would require criminal checks of persons seeking employment in public or private schools and day-care centers. Under the proposal, persons would be denied such jobs if they have been convicted of murder, child abuse, child pornography, kidnaping, assault on anyone under 15, rape or certain other sex offenses. Police would give or not give clearance of prospective employes without revealing details of their records.

A similar bill passed the Virginia Senate Friday, and is awaiting House action. Supporters of the bills in both states said they are confident of passage. If the bills pass, Maryland and Virginia would be eligible for money from a $25 million federal fund set up to help pay for the costs of the new screening programs.

The District of Columbia has no plans to institute a system of checking the criminal records of people hired to work with children, said Pauline Schneider, D.C. director of intergovernmental relations.

Long is free on $15,000 bond and on the conditions that he not live in or visit the neighborhood and that he continue psychiatric therapy. He and his wife have refused to comment on the charges pending against him and on his prior convictions. Darryl Longest, the Rockville attorney who handled Long's 1979 case, declined last week to discuss it. Another member of the law firm, Paul S. Lewis, who is defending Long against the recent charges, also declined to discuss the case.

Meanwhile, Montgomery County police said they are broadening their investigation of Long to interview up to 100 school and neighborhood children, according to county youth division detective Richard Cage.

"There are literally hundreds of kids that have taken classes over the years from Mr. Long," Cage said. ". . . Since his employment at the school in 1978, he's had access to hundreds of children in gymnastics classes, as a lunchroom monitor and as the playground supervisor. And he's the Pied Piper of the neighborhood. All of the children and the parents just loved and raved about Eric Long. That is characteristic of pedophiles -- they love children and children love them."

Among the families of the boys that Long is accused of molesting, anger is turning into a steady insistence that authorities find ways to protect children from abuse by adults.

The 8-year-old's mother said, "There's no way a parent can go around running police checks -- that's absurd. There's just an implicit trust that if your child goes to a school, everything's on the up and up -- teachers as well as coaches and everything else associated with the school."

According to police, parents and court papers, Long organized playtime activities at his house on Tabonia Drive in Silver Spring and at a nearby playground for the neighborhood boys that included jogging, playing football, catch and Frisbee, romping with his dog and baby son and rides on a motor scooter.

Long's job at the school amounted to an almost automatic seal of approval for parents in the community, said one mother.

"It all made it so much easier," she said. "We thought, 'Oh, how nice, he must be one of those jock teachers who loves to coach and be around kids and not do anything else.' . . . He really went out of his way to express a lot of good will."

At the French International School, Long was popular with parents and pupils, according to principal Rene Bernet.

"Mr. Long has worked here for a very long time. We never had any complaints against him. Instead all the parents and children liked him very much," Bernet said last week.

"We don't have any means to know if some guy has been arrested. In France, when you want to work in a school, you have to produce a record that shows no arrests . It's very important," Bernet, a native of France, said.

From 1978 until he resigned after his arrest last month, Long taught after-school gymnastic classes to boys in the third through fifth grades at the Bethesda school, supervised the lunchroom and afternoon recesses and took pictures at school functions for the yearbook.

Long also taught gymnastics to children and adults at the YMCA in Bethesda from early 1977 until shortly after his arrest in September 1979, according to Robert C. Caldwell, executive director. According to police, Long also operated his own "gym camp" in the late 1970s.

According to child protection experts and psychiatrists who treat offenders, adults who are sexually attracted to children are obsessed with their need to be around them and typically seek lifestyles that include a supply of children. If caught molesting children, they often resign their jobs and move to another area, the experts said.

Cage thinks the proposed Maryland bill would help overcome the problem of offenders moving to another community where people are not aware of their arrests because a check of police records would produce the information. "It would discourage a lot of those people who try to seek employment," he said. "That's what we really want, is a deterrent -- if we can spare the children this trauma."

But for the boys who have accused Long and for their families there is another kind of discouragement.

Said the 8-year-old boy's mother, "This has changed his life immensely in that the innocence is no longer there. . . . There's a lot of anger and hostility." She added that her son is in therapy but he will not talk to her and his father about what happened to him. "We can't change what's happened," she said, "so . . . we're trying to pick up the pieces."