Who is the real culprit according to the king? Why does he escape punishment?

According to the king the rich merchant was the real culprit as he had inherited everything from his father- both the sins and riches. Since his father was no more alive it was the rich merchant who would be held guilty.

A new stake was ordered for the execution but the rich merchant was too thin to be executed. This made the king send for a man who would fit in the stake as somebody had to be punished. This helped the man escape the punishment.