Which would make them fools in the least. Until we become omniscient, these guys ought to be under surveillance.
Observe but without fear. If the story is true. These men were commiting an act of terror. Causing fear is an important part of terror. Actual physical acts are worse, but fear a the goal. But until we make a law against acting scary and enforce it, the best thing to do is to stand up fearlessly against these swine.
If I had my way every muslim who is not a US citizen would be deported and not allowed back in. I'd watch the Muslim citizens.
But that isn't going to happen so I'll keep my eyes open and my mind clear.