Mystery of 10,000 yen

Recently, a lot of ten thousand yen bills and letters wraped with paper are founded from the rest room in the Prefectural government in the whole country.I hear that the total of the cash that has been found up to now is 3.98 million yen! Surprisingly,letters were all handwriring.Who and why put this letter and money?I think that he have to use other methods if he wants to contribute money. However, the person who found it was to have surprised and excited surely!