By Barry Moody
VATICAN CITY (Reuters) - Pope Benedict on Wednesday expressed full support for his deputy, Cardinal Tarcisio Bertone, the chief target of of leaked documents which the pontiff's butler has been charged with stealing.
Benedict's butler, Paolo Gabriele, was arrested at the end of May and charged with stealing the pope's private papers. He remains locked up in a Vatican police "safe room".
The leaked documents allege graft over the awarding of infrastructure projects and a poisonous power struggle between rival groups of cardinals - the princes of the Church.
On Wednesday, the Vatican released a letter from Benedict to Bertone, his secretary of state or prime minister, in which he said: "I wish to express my profound appreciation for your discreet support and your enlightened counsel which I have found of particular help in recent months."
The pope, who sent the letter before heading to his summer retreat of Castel Gandolfo in the Alban hills outside Rome, added:
"Having noted with regret the unjust criticism raised against you, I want to renew the expression of my personal faith in you ... which remains constant."
The arrest of Gabriele was the climax of a terrible 10 days for Benedict in May during which the head of the Vatican bank was also fired and a new book alleged cronyism and corruption in a Holy See riven by conflict between plotting cardinals.
Vatican chief spokesman Father Federico Lombardi said on Tuesday that the 50 days allowed for the initial detention of Gabriele would expire shortly and then authorities would have to decide whether to free the butler or send him for trial.
Lombardi said a trial would not take place before October, but Gabriele could be released into house arrest before then.
Vatican police and a special commission of senior cardinals have been searching for other informers since Gabriele's arrest, with many Church insiders believing the butler could only have been a scapegoat in a wider and more sinister struggle.
But Gabriele so far remains the only person under investigation, Lombardi said. The three-cardinal commission has interrogated 28 people.
Church experts say the leaks from the Vatican, involving embarrassing details about officials Bertone has appointed or removed or projects he has promoted, suggested a concerted effort to force him out of his job.
Vatican watchers suggest a rival "diplomatic wing" including Bertone's predecessor, Cardinal Angelo Sodano, was involved in the plot against the secretary of state.
Bertone is a theologian and canon law expert, in contrast to the normal choice of a seasoned diplomat for the job. He has been unpopular in some quarters for what is seen as an authoritarian style and his closeness to Italian politicians.
Benedict relies on his secretary of state to run the daily business of the Vatican and its embassies abroad while he devotes much of his time to doctrinal issues and writing a three-book study of Jesus Christ.
Lombardi said MONEYVAL, a Council of Europe monitoring group that rates states on their ability to combat money laundering and terrorism financing and their compliance with international standards, was discussing the Vatican Bank in Strasbourg on Wednesday.
But its findings were unlikely to be published immediately.
The bank, often mired in scandal in the past, drafted new financial transparency laws and internal regulations in 2010 intended to qualify for an international "white list" of states meeting international financial standards.
The Vatican bank or Institute for Works of Religion (IOR), has been in upheaval since May 24 when its president, Ettore Gotti Tedeschi, was ousted by the board. The Vatican has denied allegations by Italian magistrates that the bank may have been involved in money laundering.
(Editing by Robin Pomeroy)