The pope’s former butler Paolo Gabriele testified Tuesday that he was held in isolation in a tiny cell with the light on 24 hours a day for the first two weeks after he was accused of stealing and leaking private documents to the media.

The case -- dubbed "Vatileaks" -- saw the butler imprisoned in the Vatican police station while investigators seized 82 boxes of evidence from the apartment where he lived with his wife and three children.

The president of the Vatican tribunal opened an inquiry into Gabriele’s treatment during his detention after he told the court that the constant light had caused problems with his sight.

He also said his cell was so small that he was not able to extend his arms.

Responding to the claim in court, a spokesman for the Vatican, Father Federico Lombardi, said, "Vatican cells comply to international standards, but we are taking the accusation seriously and an inquiry has been opened."

Gabriele, 46, told a Vatican court that he was solely responsible for the leaks – confirming what he told prosecutors during the pre-trial investigation – but despite this declared himself innocent of charges of aggravated theft, saying “I only feel guilty of having betrayed the trust the Holy Father placed in me.”

L'Osservatore Romano via AP

The pope's former butler Paolo Gabriele in the courtroom of the Vatican on Sunday.

He denied he was helped by an accomplice and that he had received money or presents in exchange for the documents from an Italian journalist.

Cronyism
Gabriele admitted that in 2010 he started collecting the documents, including letters to the pope in which Monsignor Carlo Maria Vigano -- then a senior Vatican functionary -- expressed concern about improper behavior in the Holy See's business dealings.

Vigano denounced a web of corruption, cronyism and nepotism in the awarding of contracts for the maintenance of Vatican real estate to outside companies at inflated prices. Vigano was later removed from his post and sent to become the Vatican’s ambassador to Washington, seen by some as a way to push him away from Rome.

Trial of pope's former butler over leaked papers gets under way

Gabriele said that he felt disheartened by what he described as an unbearable situation. Initially, he planned only to gather information and did not intend to leak the documents to the media, he said.

He said that after leaking the documents he realized he would soon face justice and decided to turn himself in.

However Gabriele did not know how to go about this, so he confessed to a priest only known as Father Giovanni, and gave him a copy of the documents.

Vatican says the 'butler did it,' orders trial

He was asked about Vatican property allegedly found at his home.

Asked about a 16th century edition of the Aeneid, he said he just took it for educational reasons for his son and daughter. “I didn’t know the value of this book,” he said.

And of a $130,000 check found by investigators, he said: “I never saw that check in my house.” He furtherdenied having had a gold nugget at home.

Pope easy to manipulate?
Gabriele also spoke about dining with the pope.

“I had the unique opportunity to speak to him. That’s where I realized that it’s easy to manipulate somebody with such an enormous decisional power. Sometimes he would ask questions about situations he should have been aware of,” he said.

Conducted under a 19th-century criminal code, the trial began with a setback for the defense on Saturday when judges refused to admit evidence from the Church's own investigation.

Gabriele's lawyer, Cristiana Arru, hoped to explain her client's motives by admitting as evidence an inquiry by a commission of cardinals who questioned Vatican employees about the leaks.

Pope Benedict: 'Sadness in my heart' over butler leak scandal

A summary of the inquiry's results released in August showed Gabriele acted because he saw "evil and corruption everywhere in the Church," and felt the pope was not sufficiently informed.

But chief judge Giuseppe Dalla Torre said the commission of cardinals answered only to the pope and that the inquiry had "no relevance" to Vatican City's penal code.

Only evidence gathered by a prosecutor and the Vatican police will be allowed.

Facing charges of aggravated theft, the man who helped the pope dress and rode in the front seat of the Popemobile could now face up to four years in an Italian prison.

Another man, Vatican computer expert Claudio Sciarpelletti is on trial separately for aiding Gabriele.

Reuters contributed to this report.

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