An Accounting of the Free Treasure

Why would a King, in an act of mercy, sovereignly pardon a criminal sentenced to death, and entrust to him an inestimable and inexhaustible treasure, with instructions to freely give it away? Why would he not, instead, entrust it to mighty messengers from his court?  How might some respond to the offer of such a free gift? How might the king react if the pardoned criminal did not offer the treasure to others, but kept it all for himself?