Wisdom Of Birbal

One fine day, Akbar lost his ring. When Birbal arrived in the court, Akbar told him "I have lost my ring. My father had given it to me as a gift. Please help me find it.”  Birbal said ”do not worry your Majesty, I will find your ring right now.”
He said, ”Your Majesty the ring is here in this court itself, it is with one of the courtier.  The courtier who has a straw in his beard has your ring.”   The courtier who had the emperors ring was shocked and immediately moved his hand over his beard.  Birbal noticed this act of the courtier.  He immediately pointed towards the courtier and said, ”Please search this man.He has the emperors ring.”
Akbar could not understand how Birbal had Managed to find the ring.  Birbal then told Akbar that a guilty person is always scared.