In the wake of the Boston bombings, law enforcement officials are keeping a close eye on websites that provide instructions on how to make destructive devices. Authorities are now using these sites to track down potential terrorists. NBC's Lisa Myers reports.

Whoever planned and carried out the deadly bombing of the Boston Marathon may have had plenty of help, experts say, from the Internet.

“Every aspect of a terrorist attack is now managed or researched” in some way using the Internet, said Scott Borg, director and chief economist of the U.S. Cyber Consequences Unit, an independent research institute that assesses cyber threats.

“That's where people figure out what their target is, how to go after the target, it's how they learn how to make bombs, it's how they coordinate their activities with each other,” he told NBC News’ Lisa Myers in an interview.

Borg said there are hundreds of websites in multiple languages advising and instructing people how to commit terrorist acts.

Last month, al Qaeda in the Arabian Peninsula published a how-to guide that urged small-scale attacks in the United States and other Western countries using easily obtainable materials.

Titled the “Lone Mujahid Pocketbook” and published in the spring edition of the terrorist group’s “Inspire” online propaganda magazine, the guidebook borrowed from social media speak and rap lyrics to encourage Islamic extremists in the West to commit acts of violence. The guidebook also offered detailed instructions to “Make a bomb in the kitchen of your Mom,” including detailed, illustrated instructions on making pressure cooker bombs – the type of explosive authorities say was used in the Boston Marathon attack.

Richard Esposito, NBC News’ senior executive producer for investigations, calls the prevalence of online bomb-making guides “a frightening development.”

FBI via AP This image from the FBI shows the remains of a pressure cooker that the FBI says was part of one of the bombs that exploded during the Boston Marathon.

But he adds that the same websites and chat rooms that would-be jihadists use in their planning can also be a hunting ground for the U.S. intelligence and law enforcement officials looking for whoever built the Boston pressure cooker bombs.

The intelligence community is already at work there, experts say – watching for signs of imminent attacks, but also sowing disinformation and altering recipes for bombs.

“Law enforcement actively attempts to post content on these websites,” said Esposito. “They use all the investigative tools that are now available to them to thwart the terrorists online.”

So far, those methods have been very effective. And experts say the easy availability of bomb-making formulas does not seem to have increased the frequency of attacks. But they worry it may be making the successful ones more lethal.

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