It was a crime that has shocked this city to the core. On Oct. 1, 1984, a 99-pound mother of six was robbed by a group of neighborhood thugs who savagely beat her in an alley, dragged her into a garage and held her legs while one of them shoved a foot-long pole into her rectum. A jury convicted eight men in her murder, two pleaded guilty to charges in her death and police and prosecutors believe as many as 25 to 30 people may have been involved.

The trial turned on who was at the scene and who did what, not on why the atrocity occurred. That question is haunting the city.

It may never be answered. One of the people most intimately connected with the case, however, was willing to share his thoughts on the condition that he not be identified. He cannot explain the gratuitous violence, but he says the profiles of the people involved "fit every sociologist's dream of why kids go wrong." The normal controls of school, work, family and social responsibility were simply missing. The mother of two of the defendants testified, for example, that on the day of the murder she was at her sister's getting high on pot.

"There was a core group of good friends. They were all young, all relatively uneducated. You look at the school records: as early as the third and fourth grades they were not good students. They were identified real early as problems. Most didn't work. If they did have jobs, they didn't keep them very long."

They spent nights at go-go dances with thousands of kids listening to music with heavy drug overtones. They spent their days hanging out in the park. Often, he says, they did not go home for days at a time. Many had illegitimate children they did not support.

"This was a group of kids who had nothing. Some were involved in past criminal activities. Most came from broken homes."

The day of the murder they were in the park and one of them was humming a tune about getting money for PCP. Someone suggested robbing somebody and not long afterward Catherine Fuller, 48, walked by. "It's not clear anyone knew who she was beforehand. I don't think they planned to do any of the things they did. She was spunky, she must have fought back a little. One kid, I asked him why: he said, 'I don't know. Everyone was doing stuff. I wanted to show I could do stuff, too.' The dynamics of what happened have a very simple explanation: everybody wanted to be part of the group, not wanting to be seen as being afraid.

"I think this pipe thing was something Levy Rouse did on his own. There was no discussion of it. It was the horror of that that stopped it. There were seven, eight or nine people in the garage and others outside shouting, 'Let me see.' There was something very carnival-like to them. Two of the girls who testified thought it was a fight. They wandered back, then saw it was a woman. They were shocked by it but they didn't tell anybody."

One was pregnant by one of the defendants, who was then 16. Later, she refused an abortion because he might get angry. "He's got three kids already. Such a total lack of self-image and self-respect on the part of these girls amazed me. We interviewed 400 to 500 people in this. So many have dropped out of school, have no skills, no ambitions. There is so little hope of them escaping this environment they grew up in."

Two of the group turned state's evidence. A third refused. "He didn't want them to think he was weak." His relationship to the group overshadowed his sense of self-preservation.

"The thing that was most disturbing is no one came forward. There must have been a hundred people out there who'd hear about it from the people involved. That whole community just sat back and waited for the police to solve this. That makes it uglier. The cops say, 'I've never had an experience like this. I've never felt so unsupported.'

"How do you prevent it? The criminal justice system is the wrong place to start. By the time people reach this point it's too late. We put on the corrections people and the courts all these problems. I can't go out and make sure they all work and finish school.

"You have to make the opportunity easier for people so they can get out. But once people refuse to take advantage of the opportunity they're going to have to be responsible for their own lives. The one thing I'm most disturbed about is this society has given up. We've forgotten that community and all its equivalents everywhere."

Already, he says, there is talk of Fuller II among those who helped make this case. "Fuller II is all these little kids who are now 1 and 2 years old and who are going to grow up the same way."