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

Hoop Granger is a white man in Tennessee who runs a gas station that has been in his family for several generations. When a rich white man is killed down the street from the gas station, Hoop is questioned by police. Immediately, Hoop points the finger at Alvin Tinsley, a black veterinarian who worked for the dead man. Hoop is disappointed when the police do not arrest Alvin, and he decides to take matters into his own hands. Hoop, as part of the KKK, kidnaps and hangs Alvin for the crime.