As for the theory that the guy with the gloves might work at the AM/PM, I don't think so. He was shown quite a lot, and police asked if anybody recognized anyone in the video. I would think they would have shown only the other guy, since an employee would already have been identified.
Unless, of course, it is speculated that it was someone who was doing an odd-job there (cleaning the shop windows for a few bucks or something) and not known to the regular personnel.
My impression is rather some bum that wasn't allowed in the store as he might bother customers (panhandling) or stealing stuff, and leaning in the door to reason with an employee ("C'mon, man, lemme in" or asking if he could offer his services (car window cleaning) to customers at the gas pumps). Something like this.