The deadly skills used by the Washington snipers could have been learned just about anywhere: precisely why professional shooters at the world's largest gun show in Tulsa, Okla. last weekend were fearing the worst.
"We get kind of skittish about the kind of stuff that is going on because we know it's going to reflect bad on the community," says Kent Gooch, a decorated Marine who trains professional snipers outside Montgomery, Ala. He also teaches civilians how to be precision shooters.
"I'll teach a civilian how to shoot a rifle. I'll teach 'em how to use a map and compass. I'll teach 'em how to stalk a deer," he says. "What they do with that - if their sick little mind decides to go out and shoot somebody - what are you going to do about it?"
And where does one draw the line? The fact is, it may not matter.
Punch in sniper on the Web these days, and there's a virtual flood with hundreds of sites that even include videos that teach everything from camouflage to cartridges.
"There are only two kinds of snipers: the careful and the dead," says Gooch.
"I was shocked at what I found," says Tom Diaz, of the Violence Policy Center.
Diaz fears it's done more than teach; it's created a cult following of sniper wanna-bes.
"The sniper's mottos is 'one shot, one kill,'" says Diaz. "There are schools that teach civilians how to do this."
But some experts say they don't teach the kind of techniques used in the Beltway shootings.
"I don't think anyone is saying, 'OK, if you want to kill five people in Washington D.C. and not be detected, do this, and this,'" says Jim Leatherwood, a firearms expert.
And even if they did, he argues, it's not the sharing of information that's the problem.
"This is not a question of technology. This is not a question of training. This is a question of what's in this guy's mind," says Leatherwood.
And the disturbed minds are clearly there.
"Somebody will come in, for example, and ask about shooting through glass," says Gooch. "And those of us that have that information, like the military and police guys, will say, 'no, there's no need to know about that.'"
The dilemma: It's out there anyway.
"There's nothing really secret about it," says Gooch. "I mean, are you going to ban the books that have the information in it?
"Are you going to download my hard drive after I get out of the military?"
Knowledge may be power, but evil is using it the wrong way.