My brother owns some immovable properties in Mysore. But resides in Ahmedabad and executed certain documents in Ahmedabad on payment of the stamp duty.  Please inform if any stamp duty is payable on the said document to be used in Karnataka.

Any document executed outside Karnataka with respect to the properties in Karnataka is needed to be stamped.  If the amount is different, the difference should be paid after deducting the already paid stamp duty.