It said secret documents had been found at the butler's home, but that a judge would decide whether he should be prosecuted.
"Everyone in the Vatican knows him, there is a feeling of surprise and grief, as well as great sympathy for his family, who are well liked," Lombardi later told journalists. "We hope that his family can get over this ordeal."
Gabriele, who the Vatican said had "all the judicial safeguards provided for in the Vatican's penal code" faces a maximum sentence of 30 years in jail if convicted.
Nicknamed "Paoletto", the butler known for his habit of dressing to the nines, lives with his wife and three children in a building inside the Vatican, and is one of the very few lay people to have access to the papal apartments, media reported.
Always close to the pope, whether in his private chambers or travelling, he was "the first and the last" to see him on a daily basis, Corriere della Sera said.
His duties included helping the pope to dress at 6:30 am, serving his meals and accompanying him throughout the day before leaving at about 7:30 pm after serving him dinner.
La Stampa newspaper quoted an anonymous priest, who said he had once been Gabriele's confessor, as expressing strong doubts about the butler's guilt.
"He loves the pope so much that he would never betray him," the priest said.
"I have known Paolo for years... I have accompanied him spiritually and I can state that I found him a person who loves the Church and is very devoted to the popes, John Paul II to begin with and now Benedict XVI.
"What is going on is incomprehensible to me because everyone in the Vatican held Paolo in high esteem. I never heard anyone speak ill of him or any gossip about him, which is rare because in our environment you often hear slander."
He said described him as a "simple" person who could have fallen victim to a conflict with someone "very powerful" at the Vatican.
"The brains behind this plan are the same as those who supplied the media with secret documents through 'moles' with the aim of creating havoc and bringing down the Vatican government," the daily added.
Italian media said Friday that Gabriele had been working as a butler in the papal apartments since 2006. One source said the pope was "saddened and shocked" by this "painful case."
Gabriele was a member of the small team which works daily in the pope's apartments, but media reports said he was not the only suspect in the leaking of documents, some of which ended up in a new book published a week ago.
Gianluigi Nuzzi's "His Holiness" reproduces dozens of top secret and private letters and faxes which were reportedly smuggled out by whistle-blowers tired of corruption and unhealthy bitterness in the Vatican.
The number of people who have access to the pope's private study is very limited, and includes his butler, four nuns and Benedict's two secretaries, Georg Gaenswein and Alfred Xuereb.
Last month, the pope set up a special commission of cardinals to probe the leaks, which began in January and have seen a number of private documents splashed in the Italian media -- to the embarrassment and rage of the Holy See.
The documents shed light on many Vatican secrets, including the Church's tax problems, the funding of Catholic bodies, sex scandals and negotiations with hardline traditionalist rebels.
The documents have also centred on the activities of, Bertone, the Vatican Secretary of State, and of Vatican bank head Tedeschi was sacked on Thursday.