The Vatican has formally closed its latest investigation into the 1983 disappearance of an employee's 15-year-old daughter after digging up a Holy See cemetery in search of her remains.

The mystery of Emanuela Orlandi's disappearance has horrified and intrigued Italians for decades.

The cold case resurfaced last year after an anonymous tip to the missing girl's family suggested her body might be buried in the Teutonic cemetery inside the walls of Vatican City.

The Vatican had underground burial chambers near the cemetery opened and brought in forensic experts to investigate.

But tests on thousands of bone fragments determined the remains long predated Emanuela's disappearance, the most recent ones having been interred about 100 years ago.

Based on the findings, Vatican prosecutors asked for the investigation to be shelved and, on Thursday, the Vatican said its tribunal judge had accepted the request.

The case has cast suspicion on the Vatican since the teenager went missing after a music lesson in Rome.

Her relatives have demanded the Vatican reveal all it knows, and the Holy See said it agreed to search for her body last year in a show of good faith.

In a statement Thursday, the Vatican stressed that it gave the family its fullest cooperation and said the formal closing of the investigation allows the Orlandis to have access to the bone fragments for their own tests.

Speculation has swirled around Emanuela's fate ever since her disappearance, with conspiracy theories suggesting ties to the Rome mafia and the attempted assassination of Pope John Paul II in 1981.