Nine times over the past three years it's happened somewhere in the United States, and nine times stunned Americans have wondered why. A student with an irrational grudge or some deep hurt comes to school with a gun.
Deadly violence follows. Then the search for causes. And finally a renewed effort to respond in a way that ensures schools will be a place for growing and thriving, a safe place and not a place of fear or deep loss.
It's happening again this week in Littleton, Colo., where officials are sorting through the disturbing details of an attack by two heavily armed students that killed at least 15 people in the deadliest school assault in US history.
Colorado Gov. Bill Owens (R) spoke for many Americans when he stood outside Columbine High School in this Denver suburb of 35,000 and said, "We have to ask ourselves what kind of children we are raising for this to be happening all over the US."
And yet experts do not see this - or the earlier school shootings in Springfield, Ore., Jonesboro, Ark., West Paducah, Ky., Pearl, Miss., and elsewhere - as reasons for parents to be keeping children at home.
"Despite these acts, schools by far are still the safest places for your kids to be," says John Yeakey, a training specialist at the National Resource Center for Safe Schools in Portland, Ore., an agency funded by the US Departments of Justice and Education.
Overall, the rate of crime in schools has dropped slightly during the past five years, and 12 to 18 year olds are more than twice as likely to be subject to violent crime when away from school than they are when in school.
Still, about 1 in 10 public schools experiences at least one serious violent crime per year, and there has been this trend in what seems to be random gun violence. Mr. Yeakey warns that "schools need to be alert in coming months" to the possibility of copy-cat episodes.
Some schools have responded with strict prevention measures. In Fairfax County, Va., every high school and some middle schools have uniformed police officers in the hallways.
Nearly all schools in the country now have "zero tolerance" for guns and other weapons - meaning that students who come to school armed are immediately expelled.
"If students bring a gun to school, they will be gone from that school," Massachusetts Gov. Paul Cellucci (R) said last month when proposing to double the mandatory minimum sentences for having a gun on school property.
Ways to prevent violence
In order to respond quickly in cases like the one in Colorado this week in which the shooters (who apparently took their own lives) went from room to room, some schools now are able to broadcast a "lock-in code" that tells teachers and maintenance personnel to immediately lock all doors.
"We feel we have a strong system for preventing school violence," says Cindy Wakefield, senior consultant in prevention initiatives for the State Department of Education in Colorado.
Seventy-two percent of school districts in the state have prevention programs in place. These include identifying students who may be at-risk for violence, providing counseling and support services, and offering in-class training in violence prevention.
These efforts have been in place for about five years, and Ms. Wakefield says they have been effective in controlling violence.
Still, even with prevention strategies, the system is far from foolproof. "Sometimes all of our efforts aren't enough," she says. For example, during the 1997-1998 school year, Colorado school personnel discovered a total of 20 handguns brought in by students. And students say it's easy for them to gain access to a gun, she notes.
Colorado was one of the first states to pass "zero tolerance" weapons legislation. Both state and Denver leaders have been very pro-active about violence prevention, says Kathy Christie, policy analyst for Education Commission of the States (ECS), an information clearinghouse based in Denver.
"They've been on top of it," she says. "I think Colorado has done a lot."
But that didn't make Colorado immune to a senseless school shooting, nor does Ms. Christie believe that's possible. "I don't know how you can prepare for irrational acts. This is a random act of violence in the school. It's a big surprise that it happened. But it follows the trend across the country, and I think this just proves that it can happen anywhere."
But it doesn't happen everywhere, and experts say there are specific actions that can make a big difference in preventing school violence - particularly if they get to the root of the difficulties that cause such violence.
For one thing, teachers, administrators, and parents need to work toward developing an atmosphere in which students feel comfortable telling somebody in authority when they fear that a fellow student may be headed for violent trouble.
A 'gothic' clique
Speaking of the alleged shooters in Colorado this week (part of a small group that adopted a "gothic" persona), one of Columbine High's 1,800 students said, "They're really dark people. There were a lot of jokes that one day they might snap or something."
Others spoke of the suspects' fascination with guns. One student had seen one of the suspects threaten others with a gun. And yet apparently no one spoke up.
"Somebody knew something was going on in these young men's minds before it happened," says June Arnette, associate director of the National School Safety Center in Westlake, Calif., a nonprofit group that provides training programs and other resources on school safety.
"If we can just get students to make that call without feeling like they're a snitch or a tattletale."
Some blame video fantasy games and movies for inspiring violent acts. The parents of three students killed in the Kentucky school shooting filed suit last week against 25 media companies including Time Warner and the makers of the film "The Basketball Diaries," in which the main character (played by Leonardo DiCaprio) dreams about shooting his teacher and classmates.
Gun control advocates were quick to place at least part of the blame on the easy availability of guns. Some took advantage of the shootings to criticize a proposal in Colorado that would make it easier to legally carry a concealed weapon.
Supporters of the proposal said it might have made it more likely that a teacher or some other responsible adult could have stopped the killers.
In any case, school administrators around the country are developing prevention and response programs. Earlier this month, the Clinton administration launched a $300 million federal program in which grants will be awarded to 50 communities with comprehensive programs addressing juvenile violence.
"Nearly 20 states have passed legislation which either requires or recommends that schools develop 'safe school plans,' " says Ronald Stephens, executive director of the National School Safety Center.
"More schools are developing closer working partnerships with law enforcement, developing school crisis plans, and handling threats much more seriously than ever before," he adds.
"School tip lines [to report potentially dangerous students] are being implemented across the country and more alternative schools are being developed to handle disruptive students at the elementary school level," he adds.
Especially important, say experts, are communitywide programs that involve local health, law enforcement, and religious components as well as educators.
Dealing directly with managing anger and resolving conflicts "has to begin in kindergarten," says John Yeakey of the National Resource Center for Safe Schools.
It has to be part of the full curricula (and not just an occasional special class), say Yeakey and others working in the field, and it must include such things as training students to mediate disputes before they escalate to schoolyard fights or worse.
"Students must be included as part of the solution," says Dr. Stephens. "They generally know when trouble is brewing."
The age-old problem of bullying, hazing, and harassment also should be directly addressed in preventing violence, says Stephens, whose experience includes teaching and school administration.
"'Hard looks,' 'stare downs,' 'mad-dogging,' and 'mean-mugging' should be added as actionable offenses to the student code of conduct," he says. "Such threatening behavior should not be tolerated. Psychological intimidation can be as damaging as physical assaults."
"We must do more to reach out to our children and teach them to express their anger and to resolve their conflicts with words, not weapons," President Clinton said shortly after the shootings in Littleton. "And we do know we have to do more to recognize the early warning signs that are sent before children act violently."