The Vatican says a priest and a former employee have been arrested on suspicion of leaking confidential documents.
They were both members of a commission set up by Pope Francis to help reform Church finances.
Church officials believe they passed records of the commission's discussions to journalists investigating corruption within the Vatican.
The documents form the basis of two new books on the controversial state of the Vatican's finances.
by the Vatican gendarmerie at the weekend.
Clergyman Angel Vallejo Balda, 54, and Francesca Chaouqui, 33, a public relations expert, were arrested by the Vatican gendarmerie at the weekend.