The British newspaper The Daily Telegraph reported Wednesday that two of the three letters were signed by the pope's private secretary, had their contents blanked out and included an anonymous note pertaining to "shameful events inside the Vatican" and a threat to reveal the contents of the letters "if there is an attempt to hide the truth."
The accompanying note demanded the resignation of Cardinal Tarcisio Bertone, Vatican secretary of state, and Monsignor Georg Ganswein, the pope's secretary who claimed Paolo Gabriele, the pope's butler, was a scapegoat in the affair, the newspaper said.
Vatican spokesman Federico Lombardi called the note "a grave threat" to Pope Benedict XVI's leadership, adding: "Blackmail is a plausible way of defining it. We have arrived at a situation of blackmail."
The spokesman said the butler is the only person under investigation in the scandal, which has provided a rare glimpse of the power struggles within the Catholic Church in Rome.
Many of the documents leaked thus far attempt to discredit Cardinal Bertone, the newspaper said.