Once a rich merchant's house was robbed. The merchant suspected that one of his servants is the thief. He asked all his servants but all denied. So he went to Birbal and mentioned all story to the Birbal. Birbal went to merchant’s house and asked all of his servants that who stole the things. Everybody denied.
Birbal thought for a moment and an idea struck his mind, he gave a stick of equal length to all the servants of the merchant and said to them that the stick of the real thief will be longer by three inches tomorrow. He ordered all the servants to be present and meet him again tomorrow with their sticks.
All the servants went to their homes, the servant who had stolen the things thought that his stick would be longer so he cut his stick three inches and he said to himself “I am smarter than the Birbal this time”.
They gathered again at the same place the next day. Birbal asked them to show him their sticks. One of the servants had his stick shorter by three inches. Birbal caught him and said, "This is the thief."
Later the merchant asked Birbal, "How did you catch him?"
Birbal said, "The thief had already cut his stick short by three inches in the night fearing that his stick will be longer by three inches"
The merchant was very pleased with Birbal’s wisdom and gave him many gifts.