VATICAN CITY (AP) — The Holy See says a fresh investigation has been opened into allegations a future priest had sex with a fellow student at its youth seminary in Vatican City.

The Vatican on Saturday said there were "signals" starting in 2013, some of them provided anonymously, about the case at St. Pius X Pre-Seminary, which serves middle- and high school students.

It said officials at the seminary and the bishop of Como had investigated but didn't find "adequate" confirmation.

Italian journalists recently reported that the pre-seminary student was 13 years old when he started demanding sex from a younger student at night.

The Vatican says "a new investigation is underway to shed full light on what really happened."

Students at St. Pius X serve as altar boys for papal Masses in St. Peter's Basilica.