Sam and Dean visited John at the Peaceful Pines Assisted Living facility with questions surrounding the death of Frank O'Brien. They wanted to ask him about his brother Luther, who according to police reports, had died of 'physical trauma'. John told them he that he knew, and that everyone knew, that Frank O'Brien killed his brother, but no one talked about it.
John told them that when Frank's wife Jessie, a co-worker of Luther's, went missing, Frank blamed Luther as the cause of her disappearance because he had been aware that Luther had crush on Jessie, not knowing that she had committed suicide. Luther, he said, was found with a chain around his neck, and had been dragged up and down the stretch of road in front of the mill "until he was past dead."
John said he'd appealed to every cop in town, no one would look into Frank because he was considered a pillar of the community, and his brother was just the town freak. Somewhat guilt-ridden, John told them that as a widower with three children at the time, he'd convinced himself that there was nothing else he could do about it.
When it was suggested by Sam that he must have hated Frank, John replied that he did for a long time, until he realized that Frank had not been in his right mind and had only acted out of terrified fear of what had happened to his wife.