Birbal said, Jahanpanah, the thief has a straw in his beard?
Listening to this, the Emperor huffed, A straw in his beard?
While all the courtiers stood still, Alim Khan quickly ran his hand up and down his discoloured beard to pull out the straw (that never existed) before anybody else could see it.
Birbal saw him doing this and pointed out at him declaring him the thief thereby solving the mystery.
Birbal proved his wittiness once again and was rewarded with gold coins