Like, could it have been an unmarked police car? There aren't too many dark four door cars on the road at that hour - especially ones pulling into establishments that aren't open for bid'ness. Unless, of course, the car pulling in is checking/monitoring said businesses, which LE frequently does in the overnight hours.
Again, wild and unlikely speculation - which I hate to do. RELEASE THE DANG VIDEO!
EXACTLY, what I was saying (not so eloquently)!