From The Life of Saint Martin
There was a place not far from the town [Tours] and near to the monastery [Marmoutier], which the false belief of men considered to be sacred, as though martyrs had been buried there. And there was even an altar there, set up by past bishops. But Martin, not one to believe idly in rumors, sought the name of this martyr and the date of his death from presbyters and priests older than him. He felt considerable doubt because no established tradition had been passed down. For a while he stayed away from that place, neither speaking out against the veneration of the martyr, because he was unsure of his identity, nor lending his authority to the rumor, because he did not wish to strengthen a false belief. Then one day, he went to that place with a few of the brethren. Standing upon the very grave, he prayed to the Lord to reveal who this man was and the reason why he had been buried there. Then turning to the left, he saw standing close at hand a wraith that was ragged and grim. Martin commanded the spirit to speak its name and to explain the reason for its presence there. The wraith shared his name and confessed to a crime. He had been a bandit, who was executed for his wicked deeds only to be venerated by a widely held mistake. He had nothing in common with the martyrs; they had earned glory, while he had only earned punishment. Amazingly, those who had accompanied Martin could hear the voice of someone speaking, but they could not see who it was, so Martin described what he had seen and ordered that the altar be removed from that place and thereby freed the people from the error of their false belief.