Because there is no prison inside the Vatican walls, Gabriele is being held in a room inside the tiny Vatican police station.
He faces trial in a closed Vatican court and if convicted he could go to jail for up to 30 years.
Under a treaty between the Vatican and the Italian government, anyone convicted of crimes by the Vatican serves his sentence in an Italian prison.
Conspiracy and intrigue are nothing new to the Vatican, but traditionally the Vatican has been adept at keeping it inside the walls of the city-state.
Pope Benedict XVI's seven-year papacy has been consumed by public scandal.
Sexual abuse revelations by priests around the world continue to discredit the church.
In 2006, shortly after becoming pope, Benedict quoted text that inflamed Muslims around the world. He was forced to apologize.
The pope faced demonstrators Sunday accusing the Vatican of covering up evidence in the mysterious 1983 disappearance of the young daughter of a Vatican employee once thought to be buried in the tomb of a mafia don.
Asked whether all this means the pope has had a bad week, Vatican reporter Marco Politi said, "he's had a bad seven years."