The New York Times reports: At least three dozen people in the United States suspected of ties to the Islamic State were under heavy electronic or physical surveillance even before the Paris attacks, senior American officials say. But unlike the attackers in France, the officials say, the majority of those under investigation here never traveled to Syria to fight alongside the Islamic State or receive training from it.

In many ways, the officials say, that makes the American investigations even harder. Those under investigation typically have little terrorism expertise or support from a cell, which makes thwarting an Islamic State-inspired attack in the United States less like stopping a traditional terrorist plot and more like trying to prevent a school shooting.

Stopping a potential attack has taken on new urgency after Paris, which served as a reminder that even people who have already caught the eye of intelligence services can spring attacks on short notice. Although at this point American officials say there is no credible threat from the Islamic State inside the United States, they worry that Paris could provide the spark to inspire angry, troubled people to finally do something violent.

This year, American counterterrorism officials began focusing their resources on these Americans — known as homegrown violent extremists — after the Islamic State altered its tactics. After months of trying to persuade Americans to travel to join it in Syria and Iraq, the Islamic State, also known as ISIS or ISIL, began using social media to urge its sympathizers in the United States to stay put and plot violence here.

“They’re targeting the school-shooter types, the mentally ill, people with dysfunctional families and those struggling to cope with different issues,” said one senior law enforcement official who spoke on the condition of anonymity because he was not allowed to speak to reporters. “We have been pretty successful in disrupting these cases because they are not very sophisticated or smart.”

Despite the Islamic State’s urging of its followers to stay here, senior counterterrorism officials have so far identified roughly four dozen Americans who have evaded the authorities and traveled to Syria to join the Islamic State since the conflict began there in 2011, about twice the number that officials have said previously. Some of them are known to have died on the battlefield. A small number have returned to the United States but have lost interest in the cause, the officials say. [Continue reading…]