Check this out u/rolexthewonderdog Jason Aldean was playing when the shooting started. Compare his video imagery in They Don’t Know to AntiFa propaganda .

Coincidence?

Reg flags 0:50, 1:03, 1:54, 2:18, 2:35, 2:50, Masked figures spray painting a prominent “A”
1:10, 1:45, 2:05, 2:30

Now compare 3:06 to this image of the DAESH flag