By Naomi O'Leary
VATICAN CITY (Reuters) - By day, Paolo Gabriele was a member of the Vatican's innermost circle, the "papal family", possessing a key held by fewer than 10 people to an elevator leading from a small Vatican courtyard directly into Pope Benedict's apartments.
By night, he was a different man, obsessed with helping root out what he saw as corruption in the Roman Catholic Church.
The pious butler who helped Pope Benedict dress and served him his meals now finds himself on trial for aggravated theft, accused of stealing documents in what could prove to be the most sensational Vatican trial in decades.
Gabriele, 46, a reserved family man and devout Catholic, told investigators he acted for the good of the Church.
While tending to the man Catholics believe is Christ's vicar on earth, the clean-cut, black-haired butler said he saw "evil and corruption everywhere in the Church", and began leaking the papers that would cause one of the biggest crisis of Pope Benedict's papacy.
The documents, which Gabriele admits he photocopied and passed to an Italian journalist, contained allegations of corruption in the Vatican's business dealings.
His trial, which could bring a sentence of up to four years in jail, starts in the Vatican's small tribunal on Saturday.
Gabriele told a pre-trial inquiry that he never received payment for the papers, which included personal letters to the pope, but felt he was acting for the good of the Church and as an "agent" of the Holy Spirit.
"I was sure that a shock, perhaps by using the media, could be a healthy thing to bring the Church back on the right track," he said in pre-trial testimony, explaining how he felt the pope was not sufficiently informed of problems the letters outlined.
The butler, who told investigators he was in a state of confusion and disorder in the months leading to his arrest, seems to have been thrown into a crisis of conscience by insights into the inner workings of the Vatican that he encountered.
Acquaintances interviewed by investigators described a devout Catholic and a good father who lived in a comfortable apartment in the Vatican with his wife and three children.
To fathom the apparent gulf between Gabriele's acts and his appearance as a reserved and obedient servant of the pope, the Vatican summoned psychologists to determine if he could be held responsible for his actions.
The results were conflicting. One report cited in the indictment concluded that Gabriele showed no signs of major psychological disorder or of being dangerous.
But another concluded the opposite: that while he could be held accountable for his actions, he was socially dangerous, easily influenced and could "commit acts that could endanger himself or others".
The latter described Gabriele as subject to ideas of "grandiosity", as attention-seeking, and as a simple man with a "fragile personality with paranoid tendencies covering profound personal insecurity".
He turned to more than one person to share his anguish. He confided in a man he called his "Spiritual Father", referred to only as "B" in the indictment, and passed copies of incriminating papers to him as well as to the journalist.
"B" told investigators he destroyed the documents because he knew they had been obtained illegally.
The trial may shed more light on the strange case of Paolo Gabriele, the man who started out as a humble cleaner in the Vatican, slowly rose to become an aide to one of the most revered spiritual leaders, and then quickly fell from grace.
(Reporting By Naomi O'Leary; editing by Philip Pullella, Will Waterman and Mark Heinrich)