Federal cases are generally at least partially unsealed once the defendant is arrested. Especially since the charge is supposedly workplace related not terrorism etc, then someone should be able to pull the case in PACER and at least find out the basic details.
It looks more like he got injured when tackled, but the one guy blocking the camera with his body really makes it hard to tell if they're putting work in or just holding him down. Knowing cops, probably a bit of both.