To police and prosecutors, the basic facts about what happened the night of Oct. 3 in a girls' bathroom at Fort Hunt High School in Fairfax County are clear: Two boys had sex with a 15-year-old girl in a stall while a dozen other boys looked on.

After a closed trial last week in the county's juvenile court, however, it seems likely that crucial details of the incident, such as how the girl ended up in the bathroom with the boys and exactly what went on there, probably never will be established.

One thing is certain: The judicial system will not punish anyone for what happened that night. Over the course of the past two weeks, rape charges against two boys and an abduction charge against an adult have been dismissed by a Fairfax juvenile judge for lack of evidence. The charges cannot be refiled.

At two trials, no witnesses could identify who took the girl into the bathroom or describe what happened to her -- not even the girl herself. The cases against the three persons charged are "all over," a frustrated Fairfax County prosecutor Robert F. Horan Jr. said last week.

It seemed to be a surprising end to an incident that had attracted wide attention in Fairfax County and the Washington area. But Horan and other prosecutors said the conclusion was not unusual for a case involving a number of people in a confusing situation.

"It's not like everybody was sitting in an auditorium watching this the alleged assault on videotape," Horan said.

"You may have a big fight and end up with some guy cut from here to here," he said, running his finger down his neck. "And when the trial is done, no one may have been found guilty of doing it. Still, the guy was cut by somebody, no question."

Corinne Magee, the assistant prosecutor who handled the case for Horan's office, is less sanguine: "I am certain those three people who were charged were involved in exactly the ways we thought they were."

Attorneys for the 14-year-old and the 17-year-old who were charged with rape say that the innocence of their clients was upheld. But James Clark, who defended the 17-year-old youth, said his client has learned something valuable.

"The immediate lesson, of course, is that you don't hang out in the bathroom when something like this is happening," said Clark. "But it goes beyond that, to the way you lead your life. You have to be a little more cautious before you jump into a situation that in your heart you know might not be exactly right."

On the night the incident occurred, the Parent-Teachers Association was meeting in the Fort Hunt High cafeteria and the junior varsity football team was playing T.C. Williams High School of Alexandria.

Near a girls' bathroom just off the football field, a 15-year-old Fort Hunt sophomore met a group of boys from T.C. Williams. She had not met any of the boys before.

After some socializing, during which she allegedly spurned the advances of one member of the group, one of the boys picked her up, threw her over his shoulder and carried her into the bathroom, according to court testimony, and defense and prosecuting attorneys.

Once inside, they agree, the girl was placed against a tile wall and fondled. Then she was taken into one of the stalls, where prosecutors say that she was raped twice.

The girl testified in Fairfax County Juvenile Court last week that she said nothing during the incident and did not cry out or make an effort to get away, and she testified that she "didn't know why" she did nothing, according to Magee.

As the alleged rape occurred, a shifting group of teen-aged boys -- as many as 20, prosecutors say -- passed in and out of the bathroom and saw what was going on. They allegedly fled when one of the boys warned that someone had gone to alert school officials.

Magee says that the girl emerged from the bathroom crying and shaking, and that the girl told two of her girlfriends that she had been raped. She went home that night and told the same thing to her sisters, Magee said, but she made them promise not to tell their parents.

School officials learned of the incident the next day from the girl's friends, and when they called her out of class she told them the story she had told her friends and sisters.

Police and prosecutors say investigating and prosecuting the case -- proving who did what -- presented enormous difficulties.

In order to win a rape conviction, the prosecution has to prove that a sex act occurred and that it occurred without the consent of the girl.

The best witness is the victim, but the girl could not identify any of those involved by name or even pick them out, because she had not met them previously and because "she was so freaked out over the whole thing," Magee said.

Police sought to interview all those who were in the bathroom during the incident or even in the vicinity, a process, prosecutors say, that began by persuading reluctant teen-agers to provide the names of those inside, and then persuading those inside to talk.

Magee found two 17-year-old youths who, after numerous interviews with police, said they had seen sex acts performed on the girl in the bathroom and provided the names of the boys involved.

Magee expected them to testify that the two boys charged with rape "were the people who had the girl sandwiched between them there in the stall" -- as the 17-year-olds had told the police.

Instead, in court last Monday, the two testified "that they couldn't see what happened; they said the stall door was in the way," Magee said. "They also testified that the girl was hugging and kissing the older boy ," something that Magee said she had not heard before.

The two youths who ended up as Magee's star witnesses had to be pressured to talk to police in the first place, she said.

"Sure, there was pressure. None of those guys ever thought this was a rape, because they thought if she didn't want to be in there, she would have said something," Magee said. "And they never wanted to be involved; they never wanted to testify against their buddies."

"They the witnesses were told they would be held responsible if they were involved," Magee said. Both defense attorneys called this tactic coercive.

Several boys who were in the bathroom were told by school authorities that they would not be permitted to participate in school sports if they failed to cooperate with the police, Magee said. Two boys who were not called as witnesses or charged nevertheless were kicked off their school's basketball team "for their mere presence in the bathroom," she said.

It is precisely the need for that sort of pressure, say the two defense attorneys, that crippled the case from the outset and that should have made prosecutors especially leery of going forward with charges.

"When you apply that kind of coercion to people to tell a story which conforms with whatever your belief is," said William Moffitt, who defended the 14-year-old boy charged with rape, "there is a strong likelihood that the story you get is not going to be the truth."

"This case should never have been prosecuted" based on such evidence, said Clark, adding: "Where this case should have been handled was in the homes of the respective kids involved."

The attorneys for both juveniles charged with rape admit that the testimony at the trial differed sharply from the statements the witnesses had given to police.

"But the bottom line is, there is no evidence that those kids were lying at trial," said Clark. "To me, there was a strong implication they were initially just telling the police what they wanted to hear."

Moffitt says that bringing charges in the case is simply evidence "of the momentum of the system getting out of hand . . . . Somebody had to be charged with something, and somebody had to be vindicated."

Why didn't the need for such tactics concern Magee?

"I just relied on my polygraph," she said.

Before any charges were brought, one of the two witnesses was given a lie detector test, which police believe showed he was telling the truth when he said he saw several boys having sex with the girl. The story of the other youth matched well enough to convince Magee.

But Clark responded: "My client passed the same polygraph, saying he didn't have sex with [the girl]."

Magee's office is investigating the possibility of filing felony perjury charges against the two witnesses. She said she believes that the youths told the police the truth, then changed their stories in court because they had to face their friends in school.

Both Magee and the defense attorneys agree that, regardless of the outcome of the court cases, what happened in the bathroom could have and should have been prevented.

"What happened in the bathroom happened between 14, 15, 16 and 17-year-old children," said Moffitt. "It probably never was intended to be a malicious act in any sense. But it probably is an act that none of us would condone, or behavior that none of us would like our children to be involved in."

Said Magee: "All of these kids should have been better educated about how to handle a situation like this -- all of them, from my victim on down."