Who is Alvin Tinsley from The Dark-Thirty: Southern Tales of the Supernatural and what is their importance?

Alvin Tinsley is a black veterinarian living in Tennessee. Alvin was once punished for killing a cat twenty years before because Hoop forced him to make the connection. Alvin refuses to allow Hoop to pin another murder on him now as he tries to do when a local rich man is murdered. Alvin stands up for himself, even when the KKK comes and hangs Alvin for a crime he did not commit. Alvin warns Hoop that he will come back and prove who the real killer is. It seems Alvin has when each morning Hoop wakes to find the details of his crime etched on the glass of the windows in his gas station.