Kitteh in Empty Apt/House

On the way home from a client call in the Hamptons (DON'T ASK) I stopped off somewhere in Suffolk for a water and I saw a kitteh in the window of a very obviously empty home. I wrote down the address but am lost as who to call. She looked OK, a bit thin and was meowing away. ASPCA? 311? Break the window (I would drive back)? Any ideas - - I think the town was Bellport???? It was right off the William Floyd exit. . .