The Egyptian authorities have released CCTV video of the Muslim Brotherhood attempt to take over 6 October bridge, showing vanguards engaged in stone-throwing and appearing to cause fires (molotov cocktails?). h/t EAworldview
Journalist @Beltrew also reported seeing the same events unfold. The Egyptian military allege that they simply repelled this attempt to take a key overpass that connects much of Cairo. But in the course of the defense of 6 October, they clearly used excessive force and killed dozens.