She'll discover quickly that he's gone from before dawn to early afternoon, comes home to change out of his garbage truck driver uniform, and then either goes out again for most of the afternoon and evening, or putters around inside the tiny townhouse, creating a lot of very odd smells. He doesn't have a car, and he doesn't buy much in the way of groceries. What he does buy doesn't really look much like food. Also, his lawn is nothing but dead weeds, and the little planter of flowers just outside is obviously wilted and dying, despite his attempts now and then to water it.

She'll also discover he usually has the hood of a thick hoodie up over his head, and almost never goes without sunglasses, even on cloudy days: as concealed as he can be without looking suspicious about it.

And he quickly discovers there's a cat prowling around his house, and he starts looking for her out his windows, while walking down his street to and from his house, and starts leaving a little bit of cat food and a bowl of milk out on his porch for her. Just in case.