There are "good" snipers -- law-enforcement and military professionals who undergo extensive training in shooting, observation and other tactics.
But there also are "bad" snipers -- deranged individuals determined to kill innocent people. And experts say they don't have to go far to acquire the skills they need to gun down their prey.
"There's a whole menu of things that a person of the mind to be a competent sniper can find," said Tom Diaz, senior policy analyst with the Washington-based Violence Policy Center, a group that works to stem gun-related violence.
A number of magazines, Web sites, sniper schools and videos offer a plethora of detailed information for anyone who, for whatever reasons, wants to learn the skill of "one shot, one kill."
One magazine that is no longer published, Tactical Shooter, targeted a civilian audience and was devoted to the "art" of sniping.
Several Web sites also provide tips on what types of bullets and guns could be used by snipers, along with advice on the best shooting techniques.
There are even a variety of sniper "schools" to choose from, where students train to camouflage themselves and take out their enemies in single-shot, wartime or hostage situations.
"There are plenty of people out there who are fascinated with this, and, for enough money, people will train them," said Stuart Meyers, president of Maryland-based Operational Tactics, Inc., which trains law enforcement and military personnel.
That means someone with minimal training might have acquired the skill to pull of the kind of shootings that terrorized the Washington, D.C., area over the last week.
The so-called Serial Sniper "is not demonstrating precision firing," Meyers said. "It is not that difficult to shoot somebody ... any average hunter can do that."
"Give me four hours with you and I'll have you doing body shots from 100 yards -- it's not hard," added a law enforcement officer. "The guy that's doing this is not professional at all. He is not a sniper. He is nothing more than a crazed gunman."
Some facilities will train civilians who can pass security checks. While some organizations offer training for less hassle, many facilities want to make sure their ranges are free of potential evildoers.
One facility in Oklahoma trains law enforcement officers, hunters and others who undergo an extensive application process and background check before setting foot on the grounds.
The West Virginia-based Storm Mountain Training Center requires civilians to get background checks from local police department, plus a reference letter from an "upstanding person of the community" such as a doctor, priest, or police chief.
"Nobody gets in here without a clean background," said Storm Mountain President Rodney Ryan, who said the center has been "cussed out hundred of times" by civilian applicants frustrated with the security procedures.