Mike McCaul: Don't Underestimate Threat of Homegrown Terrorists

Most of the homegrown terrorism plots that have popped up since the Sept. 11 attacks have been stopped, Rep. Michael McCaul said Sunday, but the radicalization of Americans can't be underestimated, the House Homeland Security Committee Chairman said Sunday.

"Social media campaigns and the savviness of ISIS and propaganda is what greatly concerns us Homeland Security officials," the Texas Republican representative told ABC "This Week" co-host Martha Raddatz. "They can radicalize from within the United States."

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On Friday, Abdirahman Sheik Mohamud, 23, of Columbus, Ohio, pleaded not guilty in federal court to charges of training with a terrorist group in Syria to return to the United States to carry out an attack, reports ABC News, and McCaul said Sunday that the young man posed a serious threat, as there was an active plot.

"He said something big was going to happen," McCaul said. "He was plotting to attack a military installation, possibly in Texas, at the Ft. Hood purple heart awards ceremony."

But what's most significant, McCaul said, is that Mohamud marks the "first foreign fighter case of an American citizen traveling to Syria, training with Al Qaida, and then returning to the United States under instructions by Al Qaida operatives to conduct a terrorist attack on American soil."

Such operatives have been seen going into western Europe and Australia, but McCaul said "this is the first one in the United States. Fortunately, it was stopped before it happened."

And while most arrests come after potential terrorists proclaim their intentions through social media, in the case of Mohamud, a foreign fighter was heading overseas to train, and then was being directed by "top al Qaida [leaders] to conduct a terrorism attack in the United States," commented McCaul. "To me, that's very frightening."

McCaul also said Sunday that the fact that Doug Hughes, a 61-year-old Florida mailman was able to land on the Capitol lawn last week with a small gyrocopter  is disturbing.

"It's small, very difficult to detect, and can fly under the radar," said McCaul. "That's the real threat, I think. It exposed a vulnerability that terrorists can exploit. I'm meeting with officials on Capitol Hill to see what we can do to tighten up these security procedures."

Larger aircraft can be taken down if they don't respond to demands, said McCaul, pointing out that the Capitol Police told him that "they were prepared to shoot down the aircraft."

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