Investigators infiltrate Antifa and similar groups and discover a coordinated plot for bloody revolution in the US.

But you don't have to rely on confidential sources. Antifa is not trying to hide the fact that their ultimate goal is the destruction of the United States:

Antifa's war cry, "No Trump, no wall, no USA at all!" Victory for Antifa would be the destruction of society. pic.twitter.com/KiGzcg8oaG

— Hector Morenco (@hectormorenco) August 28, 2017

Black Lives Matter would also like to destroy the United States:

http://www.westernjournalism.com/black-lives-matter-leader-warns-replace-the-constitution-or-else-this-will-happen/

Blake Simons, identified as a leader in the Black Lives Matter movement, wrote an editorial with a message made clear in its title: A New Constitution or the Bullet.

 ...

In an apparent attempt to further clarify his article’s frank rhetoric, Simons wrote that “it is our human right to defend ourselves by any means necessary” and “overthrow a government that has been destructive to our people.” 

He cited failed extremist efforts of decades past, proclaiming that now is the time for blacks to “pick up where the Black Panthers left off and declare a new constitution or it will be the bullet.”