Mandalion (Спас Нерукотворный, Убрус) lost in 1204 yr in Constantinopol during the battle. Request to Above - answer: it fired (original).
Keramion, a tile, which covered Mandalion - exists. Now it is in the vaults of a some museum, it will be restored in the march of 2015 yr. Keep on waiting.
A letter to Abgar. Abgar V the Black was a historical Syriac ruler of the kingdom of Osroene, holding his capital at Edessa, one of the first Christian kings in a history. He wrote a letter to Our Lord and Jesus answered. Originals of the letters lost. Indeed, both of the letters are in the archives of an ancient monastery and will be found over 2 years.