>> The man who set off a partially detonated pipe bomb in a crowded New York subway said he was inspired by ISIS. But as police later found out, he wasn't trained by them or funded by them. The attack illustrates the rise of such do-it-yourself radicals, a major challenge for law enforcement, and an increasing threat for Americans.
Reuters Joseph Ax.>> Those people are very difficult to track for law enforcement because they don't have necessarily communications with someone overseas that the FBI can track or crack. They're not part of a cell, so they're not having meetings with other co-conspirators that law enforcement might get wind of.
And so it's quite hard to find those people for investigators.>> There have been 19 attacks perpetrated by Islamic state-inspired people on domestic soil. But unlike Europe, which has more accessible borders, the US has not had a single Islamic state directed plot. And the lack of training and support for militant organizations often limits the amount of damage.
>> And while those are obviously deadly and dangerous, they're not typically on the same scale as some of the larger, more coordinated attacks that we've seen in Europe, for example. So the Paris attacks in 2015 that were carried out by trained fighters from ISIS, directed by leaders there, and that was coordinated and a lot deadlier than most of what we see on American soil.
>> Officials say the suspected subway bomber, Akayed Ullah, learned to build a bomb on the Internet, a device which luckily failed to detonate properly. But before he tried to set off a bomb in a crowded Manhattan subway, he was not on any law enforcement's radar.