(Pope Benedict XVI conducts the holy mass of Pentecost Sunday in Saint Peter's Basilica at the Vatican May 27, 2012. REUTERS/Stefano Rellandini )

The Vatican on Tuesday denounced the theft of secret papal documents as a “brutal” personal attack on Pope Benedict as a powerful group of cardinals hunted more culprits behind the biggest crisis of his pontificate.

With the crisis over leaks of sensitive documents deepening, the third most senior figure in the Vatican fired a bitter salvo in the Vatican’s official newspaper L’Osservatore Romano.

Vatican deputy secretary of state, Archbishop Angelo Becciu said in an interview that the publication of stolen documents in a recent book by Italian journalist Gianluigi Nuzzi was a “criminal” act.

It was the first time the paper has reported on the arrest of Benedict’s butler nearly a week ago and it reflected the anger in the Holy See over what is seen as a betrayal of Benedict.