All they can tell from “ballistic evidence” would be that there are 30 caliber rifle bullets stuck n folks.
So, here is my theory:
It must have been an M1 Garand!
It would take up the whole back seat, you’d have to load a few E-blocks to shoot 13 people and those high quality peep sights wouldn’t do you much good in a moving car at night, but still, perfect for a drive by. You’ve got a bayonet and everything.
Good thing Obama stopped re-importing those things. They belong on foreign battle fields (like Omaha beach)
He used a .30 on the street.