I wonder if the cops even consider him being implicated. It’s the first thing that jumped out at me in the story. He thought the dog was abandoned when it belongs to a current tenant? Um, no.
It could be that the tenant, dog owner had been evicted and was supposed to have been out by that date. Showed up and the tenant wasn’t there, but the dog was. I could see a landlord taking the dog to the pound under those circumstances. Or if he received complaints from the neighbors that the dog wasn’t being cared for, outside all the time, they hadn’t seen it’s owner for days, etc.