It is said that Christian II, a 16th century King of Denmark, was informed one night that a courtier had been stabbed and killed in a tavern brawl. The candles had been extinguished during the fight, and the murderer was consequently unknown. Determined to discover the killer, the King had ordered all who had been present to reassemble in the tavern. One by one they were made to lay their hands over the heart of the dead man, and as the last man, a soldier, obeyed the King's command, blood trickled from the mouth of the corpse. Thereupon, the soldier broke down and admitted the murder. 

This charming little tale is the origin of the belief that when confronted with the evidence of his guilt, the criminal will confess...