Then she would fade back into her solitary forest home.
Last year, one of the office workers called Flatt, hoping he could trap the dog and find a home for her.
But at the time, Flatt was too busy to take on Shelby's case. His rescue was crammed to capacity with dogs looking for homes. Besides, it seemed the dog was at least safe and, under the circumstances, cared for.
But when someone called Flatt last week, the situation had become much more urgent. The forest where the dog lived was about to disappear to make room for development.
Knowing Shelby was out of options, Flatt rushed to the scene.
It didn't take long for him to trap Shelby, who had gotten used to food being left out for her. She followed a food bowl right into a crate and the door automatically closed behind her.
"I came back in the pouring rain," Flatt recalls. "I got out of my van and I heard whining and howling. There she was in the trap."
For a dog who spent two years on her own, clinging to the faintest hope that her owners might return, Shelby adjusted quickly to her return to civilization.