One winter morning less than two years ago, a grandmother named Mary Duncan was standing in a Kentucky high school parking lot when a 14-year-old freshman opened fire on a student prayer group, killing three kids and wounding five others.

Duncan, the 57-year-old janitor at Heath High School in West Paducah, knew the young shooter, Michael Carneal. But she had never talked to him. That fact nags at her still, and today she pushes her broom down the corridors of Heath with a mission: to seek out kids who feel angry, depressed, or sad. Known as "Miss Mary" or "Mom," she belongs to a new brigade of staff and students at Heath called Natural Helpers, a group identified by students and trained in communication skills.

"What these kids are looking for is someone who will not `narc' on them but can help them think through what they should do," Duncan says. "I just treat 'em like my own."

Heath High School principal Bill Bond considered the high-tech measures that many other schools have rushed to adopt: metal detectors, electronic surveillance cameras, video access IDs. He thought about adding another police officer to the one he already had, or requiring kids to carry backpacks made of see-through material.

But with the exception of locking several doors and posting teachers at the front of the school to look through bookbags every morning, he decided against additional external protections and went for the internal.

"When you're trying to establish a sense of security, you can surround yourself with so much stuff that you're conscious of it all the time," he says. "What really makes schools safe is kids having a sense of belonging and purpose."

To further that goal, Bond also divided the school's 600 pupils into classes of 20 each, headed by a teacher. The classes meet once a week to read and discuss a book on goal-setting and character, "The 7 Habits of Highly Effective Teens," by Sean Covey. The classes will meet weekly with the same teacher as the kids move up through the grades.

Dozens of other approaches to violence prevention have surfaced or are being tried at various schools. One recent book, "Violence in American Schools" (Cambridge University Press), a scholarly review of research and programs, lists 31 components to a safe school plan. A few of those pieces relate to what Bond is trying to do: build a social climate within a school where kids feel challenged and cared about, and where those who don't are spotted quickly and helped.

"It's worth noting that Columbine High School had a lot of technological fixes and an armed security guard and it didn't stop the violence there," says Beatrix Hamburg, a psychiatrist and co-editor of "Violence in American Schools." "The structural kinds of things may be useful but we've got to move beyond them."

Gavin de Becker, author of the best-selling "Protecting the Gift: Keeping Children and Teenagers Safe (and Parents Sane)" (Dial Press), is working on the early identification component. "You can look at any population of students and know that some are likely to act violently," says de Becker, a threat assessment expert whose clients include the Supreme Court. "The challenge is to listen when those students seek to communicate their circumstances."

De Becker is collaborating with the Bureau of Alcohol, Tobacco and Firearms to develop a computer program for schools, profiling the child who is likely to act violently. Under this plan, a child who misbehaves would be scrutinized for 10 or more factors, all weighted. Authorities might ask, for example, what kind of relationship the student has with his parents, whether he keeps a diary, and whether there are unsecured guns in his home. The assessment would be fed into a computer, which would compare his profile with that of known violent offenders. If he scored high on the threat scale, he and his family would receive help.

De Becker believes the method will be fairer to troubled kids than the idiosyncratic evaluations principals currently use. The profiling scheme is being tested in 20 schools this fall.

Rep. James Greenwood (R-Pa.) argues that such a formal identification system isn't necessary if teachers and other staff really know their students. A former social worker who works on juvenile issues in Congress, he says schools should divide their student population among the faculty, along the lines of Paducah, assigning to every child a teacher or other staff member who would be responsible for that child. Teachers and principals, he says, should be trained to recognize and act on signs of distress.

Once kids are identified, getting them real help can pose a problem. According to "Violence in Schools," many intervention programs either don't show long-term results or haven't been evaluated. Fight Crime: Invest in Kids, a D.C-based national organization of law enforcement authorities and crime survivors, has identified two successful interventions, one involving disruptive first- and second-grade boys and the other troubled seventh-graders. The kids in both groups who received special services were considerably less likely to get in trouble in later years than those who didn't.

The question that most plagues educators is how to run a school so kids don't act out in the first place. How can schools counteract the negative influences of poverty, crime-ridden neighborhoods and dysfunctional families? "Kids have a lot of problems these days," says Mary Duncan, Heath's janitor. "They come from homes where the parents are married for 20 years and then break up, or maybe their mama or daddy is an alcoholic, or their brother is a drug addict."

Duncan's boss, Bill Bond, says the answer is to get better at "the business of education."

Bill Modzelski, director of the Department of Education's Safe and Drug-Free Schools Program, agrees. "A safe school is a good school," he says. That means building smaller schools or dividing up large schools into several smaller, self-contained units, "so teachers know who's in their classrooms." It means providing challenging courses for kids when they are in school as well as attractive activities after school, that unsupervised time when disturbed kids tend to plot their violent schemes.

`THEY'RE TAKING AWAY OUR LIFE'

Five of the country's brightest students -- designated Youth of the Year finalists by the Boys & Girls Clubs of America -- recently shared their thoughts about security restrictions at their schools.

Martin Banda, 17, Harlingen, Tex.: "All the bags we carry have to be see-through. I don't want everyone to see my jock strap. They're destroying a lot of the pride we had in our school."

Natasha Goffredo, 18, Philadelphia: "We used to hang out at our lockers in the morning before class. That was the only time in the day when we could really socialize with our teachers. Now we have to go to the cafeteria until our first class starts."

Lisa Bell, 17, Lewiston, Idaho: "The day after Columbine, they made this kid who wore a trenchcoat to school take it home. He had always worn that trenchcoat. Everybody knew him."

James McGhee, 17, Maywood, Ill.: "They spent $1 million at my school on cameras and other surveillance. You weren't supposed to walk anywhere without a pass. But I was a popular kid. I could walk around wherever I wanted."

Amber Hudson, 18, Jackson, Miss.: "We had to have IDs for ourselves, IDs for our cars. We couldn't get into school early to study. They don't realize, school is our entire life. They're taking away our life."