He was carrying the backpack. After he jumps, he has the bag in his hand, and as he starts running, he slings it over his shoulder and puts the straps over the other shoulder. It’s not a long gun. How did he have time to take it apart?
IMO, that was not a backpack he was carrying, why not put it on his back, it takes no time, you can do that running across the roof, he was definitely carrying a long rifle
“How did he have time to take it apart?”
Practice.
There was a gun in the bag, why have the bag otherwise. I doubt the perp was worrying about bringing home his books to study. I have heard no evidence that the supposedly found Mauzer rifle is actually the kill weapon. If it exists, the bullet that killed CK has to be found and see if it matches the gun. There are other type guns that brake down fast that could have been used.
Something else hit the ground. Watch on a screen larger than the phone and you’ll see it.
But it doesn’t look like a full rifle. Barrel, perhaps.
‘Perhaps’...which raises more questions.