CAIRO- As an inquest into the death of Egyptian billionaire Ashraf Marwan opens in London today, Mona Gamal Abdel Nasser, his wife, has accused Israel's intelligence agency, Mossad, of assassinating him. "Ashraf confided to me that he was being pursued by assassins nine days before his death. I believe he was killed by the Mossad," Mona, the daughter of late Egyptian President Gamal Abdel Nasser, said. She expects to be a witness at the coroner's inquest. Mona, Marwan's wife of 40 years, has criticised the investigation by the Metropolitan Police into Marwan's death as below the par. "The shoes that Marwan was wearing when he died …quot; which may have provided vital DNA evidence to show whether he was murdered or jumped …quot; were lost by an investigating officer," she told the British newspaper The Observer. The billionaire arms dealer, who was the son-in-law of Egypt's second president, fell to his death from a fifth-floor West End balcony on a summer's day in 2007. His death in the heart of wealthy London made world headlines. An inquest this week will attempt finally to unravel the circumstances of Marwan's fatal fall. In an exclusive interview, his widow told the Observer that in the days before he died her husband believed his life was in danger. After Marwan died, his family discovered that the draft manuscript of his memoirs …quot; which threatened to expose secrets of the Middle East's intelligence agencies …quot; had disappeared from his bookshelf. Since his death, there has been intense speculation over the secretive life of Marwan and his role in the Yom Kippur War, waged between Israel and a coalition of Arab states backing Egypt and Syria in October 1973. Mossad agents said Marwan was their heroic spy at the heart of the Egyptian Government. But both Hosni Mubarak, Egypt's current President, and the former head of Israeli military intelligence have indicated that Marwan was a double agent feeding misinformation to the Israelis. Mona, speaking from her home in Cairo, said that Marwan told her three times in the four years before he died that his life was in peril. The last time he did so, they were alone together in their London flat. "He turned to me and said: 'My life is in danger. I might be killed. I have a lot of different enemies.' He knew they were coming after him. He was killed by Mossad," she said. A police spokesman said that the three-year investigation into Marwan's death, which was removed from one set of detectives and handed to the Specialist Crime Directorate after Marwan's shoes were lost, continues. The coroner's inquest has been scheduled to last for at least three days, and is expected to hear testimony from police officers and from former business partners of Marwan.