(USA TODAY) - As most Americans this week enjoy mid-April's well-deserved warm weather, educators, law enforcement and civil rights groups are perhaps understandably a bit on edge with the approach of several dates that bring bad memories.
Saturday marks the anniversary of the 1995 terrorist bombing in Oklahoma City, as well as the 1993 FBI attack of the Branch Davidian compound near Waco, Texas, which killed cult leader David Koresh and 75 followers.
Oklahoma City bomber Timothy McVeigh called his attack payback for the deaths at Waco at the hands of the FBI, calling the siege "first blood." The Oklahoma City bombing killed killed 168 people.
Six years later, Colorado teenager Eric Harris would boast in his journal that he planned to outdo McVeigh's body count in an attack on Columbine High School in Littleton, Colo. The 15th anniversary of that attack falls on Sunday. Harris, along with Dylan Klebold, killed 13 in a siege that was actually a failed bombing, police say. The Columbine attacks took place on the 110th anniversary of Adolf Hitler's birth.
"These are key dates on the calendar of the radical right," says Mark Potok, senior fellow at the Southern Poverty Law Center in Montgomery, Ala., which tracks hate groups.
Many people in the militia movement see April 19 as significant for several reasons, Potok says. For one thing, it's the anniversary of the first shots fired at Lexington and Concord, Mass., which effectively began the American Revolution. It's also the anniversary of the first day of the 1943 Warsaw Ghetto Uprising during World War II.
"Many people in the anti-government militia movement see it as this big day for freedom," Potok says. "Of course, it's also (the anniversary of) right-wing radicals murdering large numbers of people."
April 19 in particular has been significant in law enforcement circles since the 1995 Oklahoma City bombing.
For years, schools each spring have endured annual "Remember Columbine" bomb scares and violent threats invoking the Colorado attacks, which have become a sort of cultural touchstone among a few disaffected youths. Last week also marked the seventh anniversary of the 2007 Virginia Tech shootings, which killed 33 people.
School-safety experts say springtime in general is a stressful time for students, who are preparing for exams and socially stressful situations such as prom and graduation day.
"Whenever you see people under stress, you can see threatening behavior," says Marisa Randazzoof Sigma Threat Management, a Virginia-based training and consulting firm. Randazzo is a former chief research psychologist for the U.S. Secret Service who was on the panel that in 2000 applied its "threat assessment" model to examine the behavior of 41 school attackers over the previous 26 years.
What they found was that there was no good "profile" of the type of person who becomes a school shooter. Rather, they found similar patterns of behavior. School shooters didn't just "snap" and begin shooting impulsively. They planned, sometimes for weeks. In almost every instance, the attacker gave those around him cause for concern beforehand: trying to get a gun, writing poems in English class that talked about suicide or homicide. In one case, a student began talking about a way to poison people in a pizza restaurant.
Randazzo agrees that for educators at this time of year, "their antennae are up," but adds, "We need those antennae up all times of year." Paying attention to changes in kids' behaviors and regularly conferring with one another about smaller threats is key to heading off bigger ones, she says. Of the attackers the Secret Service studied, "Nearly all of them had seriously troubled one or more adults," she says. "These are not kids who were invisible — they actually were on multiple radar screens."