Two tombs in a small Vatican cemetery are to be opened tomorrow following a request from the family of a teenage girl who disappeared in 1983.

The Vatican City State tribunal made the order to open the graves last week.

Emanuela Orlandi, a Vatican City resident and the daughter of a Vatican employee, disappeared in Rome in June 1983 when she was 15.

In March, a lawyer for the family revealed they had been sent a letter with a photo of an angel above a tomb in the Vatican's Teutonic Cemetery, a medieval cemetery now reserved mainly for German-speaking priests and members of religious orders.

Once the tombs are opened the remains inside will be inventoried and catalogued before tests are conducted on the age of the remains and their DNA. This process could take weeks.

A statement said the graves would be opened on 11 July in the presence of representatives of the missing girl’s family.

Emanuela's disappearance in 1983 is one of the most enduring modern mysteries of the headquarters of the Catholic Church and has been the subject of much speculation by Italian media.

She was last seen on the 22 June 1983 at a bus stop in the centre of Rome on her way home from a flute lesson.

There have been many reported sightings of her over the years, even inside Vatican City, but all were deemed unreliable.