The arrest of Christopher Lee Cornell, an Ohio man who planned a terror attack on the U.S. Capitol building, isn't the first time the FBI foiled a plot masterminded by a homegrown radical.

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In 2012, the agency engaged in an undercover operation against 29-year-old Amine El-Khalifi, who also had plans of an armed assault on the U.S. Capitol.

The FBI released disturbing new video of the sting, which shows several agents posing as Al Qaeda operatives ready to help El-Khalifi obtain bombs and guns.

The video includes harrowing shots of El-Khalifi familiarizing himself with a submachine gun in a motel room before the group goes to a hardware store to buy nails for a bomb.

The video later shows them testing the bomb in a quarry. When he sees it explode, El-Khalifi comments, "Brother, this is not strong enough."

El-Khalifi was arrested and is currently serving a 30-year prison sentence.

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Former Assistant FBI Director Steve Pomerantz appeared on "America's News Headquarters" today and said that the first line of defense against homegrown terrorists is intelligence.

"We have to try to stay ahead of them by knowing who they are, where they are and what they're planning to do," Pomerantz said.

"This is not a problem that's about to go away," he added. "No way are we anywhere near being out of the woods on this yet."

Watch more above and get analysis from Kirk Lippold on how the U.S. military can combat unconventional terror attacks in the clip below.

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