Va. Code Ann. § 29.1-561

No person shall be excused from testifying for the Commonwealth as to any offense committed by another under the provisions of the game, inland fish and boating laws by reason of his testimony tending to incriminate himself, but the testimony given by any such person on behalf of the Commonwealth when called as witness for the prosecution shall in no case be used against him, nor shall he be prosecuted as to the offense to which he has testified.