The Vatican has said a high-ranking official is suspected of leaking classified information to the media. It marks the second time in several years such a scandal has rocked the institution.
A priest was one of two people arrested on Monday in connection with the apparent security breach, the Vatican said.
Spanish priest Lucio Angel Vallejo Balda and laywoman Francesca Chaouqui were held under suspicion of leaking the sensitive material to two Italian journalists. Both were members of a commission set up by Pope Francis to examine reforms related to Vatican bureaucracy.
Vallejo Balda and Chaouqui were arrested over the weekend for questioning. Chaouqui was released on Monday after cooperating with authorities.
The Vatican's announcement comes the same week the two Italian journalists are each slated to publish a book containing sensitive information regarding the Church.
It is not the first time the Vatican has been rocked by such a scandal.
In what became known as the 'VatiLeaks' incident, Pope Benedict XVI's butler leaked documents to the press in 2012. One of the books that was published in the wake of the scandal was written by Gianluigi Nuzzi, who was also involved in the most recent controversy.
In 2013, a law was passed making it illegal to leak Vatican information.
blc/jm (AP, dpa, Reuters, KNA)