I originally heard the story as guy admits to being a werewolf at a werewolf tribunal. Claims he's a werewolf in God's service and he and other fellow werewolves travel to Hell to fight witches who steal crops and whatnot. And they let him go. From there I decided I liked the idea of that the church clergy were so credulous in their belief of the superstitious that any sufficiently fantastic story would be convincing for them.
The actual story I found is a bit different from the synopsis account, but it is an interesting tale concerning Thiess_of_Kaltenbrun. The short story is no one cared that he claimed to be a werewolf because most people didn't actually think it was true. The trial he was at had nothing to do with him, but rather a burglary at the local church that the judges believed he had been a witness too. Even though the trial had nothing to do with him being a werewolf it sounds like he felt the need to tell the whole story at length, something an old person in the eighties is often wont to do. The Judges thought he might be mad, but most people in town thought he seemed sane enough. Thiess also practiced folk magic, which I guess they took a little more seriously. He was flogged and banished because his spells didn't mention God.