VATICAN CITY (AP) — The Vatican spokesman says authorities are working on recovering a letter written by Michelangelo that was stolen from an archive in 1997.

The Rev. Federico Lombardi said the Vatican has recently been offered the return of the letter in exchange for a payment, but that officials have refused. Instead, the spokesman said the matter has been turned over to the Vatican gendarmerie for further investigation.

Lombardi was responding to a report in the Rome daily il Messaggero that said a former employee of a Vatican archive has asked a ransom of 100,000 euros ($108,000) to return the letter.

According to il Messaggero, the letter is a rare example of Michelangelo's handwriting, and contains his signature.