The cardinals were given a broad mandate to interview Vatican officials across the board to get to the bottom of the leaks and report back to the pope. They are working separately from a criminal probe headed by the pope's top bodyguard, a former Italian secret service agent who heads the Vatican police force.
So far only one person has been arrested in the case: the pope's butler, Paolo Gabriele, a 46-year-old father of three who was arrested May 23 and accused of aggravated theft after reams of papal documents were found in his Vatican City apartment.
He is to undergo a new round of interrogation next week by the investigating judge after a week-long hiatus.
The Vatican said Saturday that Benedict would meet later in the day with the commission investigating the leaks. It is headed by one of the Vatican's top legal heavyweights: Cardinal Julian Herranz, an Opus Dei prelate who led the Vatican's legal office as well as the disciplinary commission of the Vatican bureaucracy before retiring.
The leaks scandal broke in January when Italian journalist Gianluigi Nuzzi revealed letters from a former top Vatican administrator who begged the pope not to transfer him for having exposed alleged corruption that cost the Holy See millions of euros (dollars) in higher contract prices. The prelate was transferred and is now the Vatican's U.S. ambassador.
The scandal widened over the following months with documents leaked to Italian journalists that laid bare power struggles inside the Vatican over its efforts to show greater financial transparency and comply with international norms to fight money laundering.
The scandal reached a peak last month when Nuzzi published an entire book based on a trove of new documentation, including personal correspondence to and from the pope and his private secretary, much of which painted the Vatican secretary of state in a negative light.