This is why every mosque in the United States should be put under heavy surveillance now. This is war against the Western Culture.
The only way to handel this situation is never turn your bach on them.
Mosques should be closed and Islam banned in civilized nations. Islam is incompatible with freedom and will not coexist peacefully with anyone. It doesn’t matter what Muslims believe (or pretend to believe), the Koran, which is their guide for life, clearly teaches that the world must submit to Sharia. If there are moderate Muslims, they are heretics according to the Koran.