ROME >> A mysterious source named Maria. A room furnished with a single chair, where sensitive Vatican documents are turned over to an investigative journalist at regular meetings. The arrest of the pope’s butler. Perhaps the greatest breach in centuries in the wall of secrecy that surrounds the Vatican.

An on-again, off-again scandal that the Italian press has called VatiLeaks burst into the open Friday with the arrest by Vatican gendarmes of a man, identified in news reports as Paolo Gabriele, the pope’s butler, who the Vatican said was in possession of confidential documents and was suspected of leaking private letters, some of which were addressed to Pope Benedict XVI.

The arrest follows by a day the ouster of the president of the Vatican Bank, Ettore Gotti Tedeschi, amid conflicts over how to bring the secretive institution in line with international transparency standards and days after the publication of a sensational book, “Your Holiness: The Secret Papers of Benedict XVI,” in which the journalist Gianluigi Nuzzi, aided by “Maria,” discloses a huge cache of private Vatican correspondence, many with allegations of mismanagement at the Vatican bank and cases of corruption and cronyism.

The letters, which have made their way into the Italian news media in recent months, draw a portrait of an ancient institution in chaotic disarray behind its high, stately walls, where various factions vie for power, influence and financial control in the twilight years of Benedict’s papacy.

“Of course there are problems, big problems,” said Andrea Tornielli, a Vatican expert for the Italian daily La Stampa and its website, Vatican Insider. “What is happening now shows that there’s a crisis.”

It was not clear whether the bank president’s ouster and the arrest of the man found with confidential documents were directly related, although Nuzzi’s book includes various memos from Gotti Tedeschi about the Vatican bank.

The Vatican spokesman, the Rev. Federico Lombardi, declined to identify the person who was arrested, saying only that he was not a priest or member of a religious order and that he had been detained for further investigation.

But Italian news media reported that he was Gabriele, 40, and a butler in the papal household. Some publications even showed images of him holding a white umbrella above the pope and pouring him wine at dinner.

The twist that “the butler did it” was fully worthy of a whodunit that began earlier this year when documents began appearing in the Italian press. In one, a Sicilian cardinal, writing in German in order to be more stealthy, said he had heard in China about a bizarre plot to kill the pope. At the time, Lombardi called the accounts “delirious and incomprehensible.”

In another letter from 2011 that appeared in the Italian press this year and is also published in Nuzzi’s book, Archbishop Carlo Maria Vigano, then the deputy governor of Vatican City, wrote directly to Benedict. In it, he argued that transferring him to another post would impede his efforts to fight “corruption and abuse” in various Vatican offices, sending the wrong signal about his efforts to rein in cronyism in the awarding of contracts for construction work at the Vatican.

Nevertheless, the Vatican secretary of state, Cardinal Tarcisio Bertone, named Vigano papal nuncio to Washington, where he has had to contend with multimillion-dollar lawsuits against U.S. dioceses over the sexual abuse scandal that has plagued the Roman Catholic Church, according to Nuzzi’s book.

At a news conference this week, Nuzzi said he believed that his source had been motivated by “courage, as well as the unbearable complicity with people that are committing the most serious crimes.”

He added: “I think that 20 years ago this book would have never come out. There are documents that hint at relations between states, and that’s why I think they are very relevant; they are not private documents regarding the Holy Father or one of the cardinals.”

The release of documents in which Vatican officials discuss one of the great unsolved mysteries in Italy, the 1983 disappearance of Emanuela Orlandi, the 15-year-old daughter of a Vatican employee, led to the reopening of a criminal investigation.

The book also provides a window into the nexus between Italian banking and media power and the Vatican. In one letter from last Christmas, Bruno Vespa, Italy’s most well-known television host, sent a check for $12,500 to the pope’s private secretary, Monsignor Georg Gaenswein, “a small sum at the disposal of the pope’s charity,” and asked when he could have a private audience. The director of Italy’s Intesa San Paolo bank, Giovanni Bazoli, sent a $32,000 check, “with my most deferential salutations.”

Other letters addressed to Gaenswein are written in obsequious baroque Italian, in which everyone from Jesuits to officials in the government of former Prime Minister Silvio Berlusconi to Mercedes-Benz directors responsible for maintaining the popemobile write seeking favors, recommendations and, most of all, the pope’s ear.

But other documents hint at more complex dealings. In one letter, Gotti Tedeschi defends himself to Gaenswein after he and another Vatican bank official had been placed under investigation by Rome magistrates in September 2010 for having failed to adequately explain the origins of funds transferred from one account held by the Vatican bank to two others it holds.

Since so many documents have been leaked from the Vatican this year, there were some doubts expressed that the butler arrested Friday was the true — or only — source.

“It doesn’t seem likely that he is the only one responsible for VatiLeaks because many of the documents that came out didn’t ever pass through the pope’s apartment where he works,” said Paolo Rodari, a Vatican expert for the Italian daily Il Foglio. “His arrest seems more the Vatican’s desire to find a scapegoat.”

Bertone has emerged as a central, contentious figure in the VatiLeaks drama. Many critics, including some inside the Vatican, see him as a poor administrator who as the Vatican’s CEO has struggled to manage the scandal-ridden papacy of a German intellectual with little interest in day-to-day affairs of state. Vatican observers say that many of the leaked documents are aimed at undermining the cardinal’s influence.

That clash has played out most visibly in the controversy over the Vatican bank, which has struggled to comply with international anti-money-laundering standards. Defenders of Gotti Tedeschi see him as trying to improve the transparency of the Vatican finances, while they see Bertone as trying to impede his efforts.

In a statement Thursday, the Vatican said simply that the five-member board of the Vatican bank had voted no confidence in Gotti Tedeschi “for not having carried out functions of primary importance for his role.”

Others familiar with the Vatican bank said that Gotti Tedeschi had not been fully involved in the oversight of the bank because he maintained his full-time job as the head of Italian operations for Spain’s Banco Santander in Milan.

Friday, Reuters reported that Gotti Tedeschi had said, “I have paid for my transparency,” while the Ansa news agency reported that he was torn between “telling the truth and not disturbing the pope.”

© 2012 The New York Times Company