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.
She disappeared at 15. A cryptic tip-off in the Vatican could hold the key to her case
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.
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.
On Thursday the Vatican began an operation exhuming two tombs inside the Teutonic Cemetery, a pretty courtyard adjacent to the grand Saint Peter's Basilica, which is reserved for the burials of German-speaking Catholics.
Like so much of the Vatican and its institutions, the graveyard is largely hidden from the public, tucked in behind high walls and glimpsed only through ornate metal gates.
In summer last year, the Orlandi family received the latest in a long list of anonymous tipoffs: A photo of an angel sculpture, and an instruction to "look where the angel is pointing."
The message led the family to two tombs inside the Teutonic Cemetery.
After campaigning from the Orlandis, the Vatican announced earlier this month it would exhume the contents of those tombs.
"Until I don't find Emanuela's body, for me it's a duty to look for her alive," Orlandi told CNN, ahead of the exhumation.
If his sister's remains are there, it is "at least part of the truth," he added. "Then I would like to know the reasons why."
"Even if nothing was to be found, it cannot be the end of the story," he said.
The operation is a complex one, involving Vatican security forces, construction workers and machinery, Vatican spokesman Alessandro Gisotti said last week.
Any bones found during the search would have to undergo laborious DNA analysis, which could take weeks, he added.