She disappeared at 15. A cryptic tip-off in the Vatican could hold the key to her case

Emanuela Orlandi, pictured as a child.

Rome (CNN)On a sweltering summer's evening in 1983, a 15-year-old girl packed her flute and walked out of her family home inside the vast walls of Vatican City.

Emanuela Orlandi had made this journey, from her apartment to a music lesson in central Rome, countless times before.
The daughter of a prominent Vatican employee -- her father Ercole worked as a clerk in the pontiff's household -- Emanuela would take the bus outside the holy city to classes at Sant'Apollinare basilica.
    Her older brother Pietro remembers theirs as a charmed childhood: the Vatican's spectacular gardens were their playground, and Pope John Paul II would stop by and talk to the youngsters having fun on the manicured lawn.
    "We thought we were in the safest place in the world," he said, explaining that the city was more like a village, inhabited by a closely-knit group of around six families.
    Emanuela Orlandi disappeared in 1983 on her way home from a flute lesson.
    But on this particular day, June 22, Emanuela never returned home from her music lesson.
    What followed is a mystery that has gripped Italians for more than three decades, inspiring conspiracy theories involving everyone from mobsters to international terrorists and the highest echelons of the Vatican.
    Pietro Orlandi, today in his 60s and with a shock of white hair, has relentlessly pursued each lead in a 36-year campaign to reveal what happened to his beloved sister.
    Now he hopes to find the answer in a small graveyard, just a few hundred meters from where their mother Maria still lives, inside the city walls.
    Pope John Paul II with Emanuela Orlandi (pink sweater, center), and (from right) her brother Pietro, father Ercole, and mother Maria.

    Look where the angel is pointing

    On Thursday the Vatican began