An Italian girl whose disappearance 25 years ago baffled investigators was murdered and thrown into a cement mixer by the gang which kidnapped her, according to a new witness.

Police this week re-opened the inquiry into the disappearance of Emanuela Orlandi, the daughter of a Vatican employee, in June 1983 following new evidence from a former mistress of the leader of the Banda della Magliana (Magliana Gang), Rome's most notorious underworld gang.

The gang allegedly kidnapped Ms Orlandi as part of a plot to put pressure on the Italian authorities to release Mehmet Ali Agca, the Turkish gunman who tried to kill Pope John Paul II on St Peters Square in May 1981.

Some investigators have speculated that Ms Orlandi, who was 15 at the time of her disappearance, was passed by the Magliana Gang to the Turkish ultra right "Grey Wolves", to which Agca belonged, and who are said to have organised the attempt on the Pope's life in league with Bulgarian agents acting on behalf of the KGB.

According to this theory Ms Orlandi, who would be forty if still alive, came to identify with her captors and became a Muslim, living in either Turkey or Paris.

However the unnamed witness, the former mistress of Enrico De Pedis, the Magliana Gang boss, has told police that Ms Orlandi was killed. Her body was then put into a sack and thrown in a cement mixer at Torvaianica, an area of sand dunes on the coast near Rome.

Questioned by Rome prosecutors, the witness said Ms Orlandi had been held prisoner at a building near Piazza San Giovanni di Dio, not far from the Vatican, which had "a huge basement". However the girl was later murdered because she had become a liability.

The witness said that De Pedis - who was known as "Renato" or "Renatino" - had taken her to lunch in a restaurant in Torvaianica, where they met his driver, who had two sacks in his car. "He said he had the body of Emanuela Orlandi with him. I don't know what was inside the sack because I stayed in the car. He said though that in was better to get rid of everything, that's what he thought. Destroy everything so that there would be no evidence, nothing left. He told me that he had thrown those two bodies into that cement mixer."

They had gone to a building site, where "at a certain point they started the cement mixer," putting the sacks in it. "Afterwards I asked Renato: 'Hey, what was in there?'. He said to me, it's better to kill them straight away, get rid of the evidence straight away".

The witness said she believed the body in the other sack was that of Domenico Nicitra, the eleven year old son of Salvatore Nicitra, a rival gang boss. However, the Corriere della Sera newspaper said Domenico Nicitra and his uncle Francesco had disappeared much later, in June 1993.

Ms Orlandi disappeared after taking flute lessons at a music school near Piazza Navona in the centre of Rome. She told her sister she had been offered a summer job by a cosmetics firm and was meeting its representative. She was later seen by eyewitnesses getting into "a dark BMW", and has not been seen since, even though Rome was plastered with "missing" posters and Pope John Paul appealed for her release.

The Orlandi family subsequently received anonymous phone calls from the alleged kidnappers - some with rough Roman accents but one with "an American" accent - offering to release their daughter in exchange for Agca, who was imprisoned in a high security jail. Secret negotiations came to nothing however.

There have been reported sightings in Rome of Ms Orlandi, but none has ever been confirmed. While in prison in Italy, Agca, who has since been extradited to Turkey, told an interviewer he had no "direct knowledge" of Ms Orlandi's fate, but believed she was alive and "living in a cloistered convent".

The involvment of the Magliana Gang surfaced three years ago when an anonymous caller to "Chi L'Ha Visto?",an Italian TV programme on missing persons, suggested the clue to the mystery lay in the fact that De Pedis - who was gunned down by rival gangsters near Campo de Fiori in the centre of Rome in February 1990 - was buried in the crypt of the church of Saint Apollinaris, next to the music school which Ms Orlandi attended. It remains unclear why a top criminal was given the honour of burial in a crypt normally reserved for cardinals, saints and martyrs.

Natalina Orlandi, Emanuela's sister, said she would not believe that her sister was dead "until we have definite proof." Maria Orlandi, her mother, said she hoped Pope Benedict XVI would now issue an appeal to other witnesses to "search their consciences"and "break their silence" about Ms Orlandi's fate.

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