One day a man robbed another man of all his money. The officer in the village called all the suspects together and gave them all a stick.
"Overnight" he said "the guilty persons stick will grow 1 inch in length, tommorow when these sticks come back we will now who did it"
The next morning all the suspects were together with there sticks which were all the same size. However, one was shorter than the rest. The owner of that stick was locked up for commiting the crime. Later that day he confessed for the crime and gave back all the money.
How did he know he did it?