VATICAN CITY (AP) — The pope's butler was convicted today of stealing the pontiff's private documents and leaking them to a journalist in the gravest Vatican security breach in recent memory. He was sentenced to 18 months in prison, but the Vatican said a papal pardon was likely.

Judge Giuseppe Dalla Torre read the verdict aloud two hours after the three-judge Vatican panel began deliberating Paolo Gabriele's fate. Gabriele stood impassively as it was read out in the tiny wood-panelled tribunal tucked behind St Peter's Basilica.

The sentence was reduced in half to 18 months from three years because of a series of mitigating circumstances, including that Gabriele had no previous record, had acknowledged that he had betrayed the pope and was convinced, "albeit erroneously" that he was doing the right thing, Dalla Torre said.

For now, he is serving his sentence under house arrest.

Gabriele was accused of stealing the pope's private correspondence and passing it on to journalist Gianluigi Nuzzi, whose book revealed the intrigue, petty infighting and allegations of corruption and homosexual liaisons that plague the leadership of the Roman Catholic Church.

He has said he leaked the documents because he felt the pope wasn't being informed of the "evil and corruption" in the Vatican, and that exposing the problems publicly would put the church back on the right track.

In his final appeal to the court Saturday morning, Gabriele insisted he was no thief.

"The thing I feel strongly in me is the conviction that I acted out of exclusive love, I would say visceral love, for the church of Christ and its visible head," Gabriele told the court in a steady voice. "I do not feel like a thief."