Since they still had the tags and part of the rack still attached to them, I would check the dumpsters in the apartment complexes just north. These guys were pretty good. And how does Dick's not have roll up doors? Or outside cameras?
I was thinking they either had a van or pickup with a shell on the back for their getaway. I'd also bet they have these guys on in-store video visiting the store during business hours or a former employee is in on it.