Two things:

They found the creep, er sorry, "person" of interest on Ashford Dunwoody Road, at a convienance store (there aren't too many on AD Road...so only about three probable pick up locations).

Meredith's dog Ella was found at a Kroger in Cumming.

I thought Vogel and Cumming were a bit far, so I checked a state parks map, and I'm right. While it's possible that the dog could have covered that much terrain in three days, it's not likely. How did Ella get to that Kroger?