Imane Fadil, 34, died March 1 at a Milan-area hospital, where she had been treated since January 29 for exhibiting "symptoms of poisoning", Milan prosecutor Francesco Greco said, according to the Italian news agency ANSA. The news agency ANSA said a toxicology test had found that she had been killed by a "mix of radioactive substances". Italian newspapers reported that she was writing a book about her experiences and that the magistrates had obtained a copy of the manuscript following her death. "What I read were her declarations that made me always think these were always invented and absurd things".
Berlusconi was initially convicted in the case but ultimately acquitted after a judge ruled he could not have known the underage prostitute was in fact a minor.
Mr Berlusconi - who has served as prime minister in four governments - is still facing a number of charges, including bribing.
The model claimed to friends and her lawyer that she had been poisoned, according to the report.
Francesco Greco, Milan's chief prosecutor, told Reuters: "Initial medical record checks suggest some form of poisoning so we are having a full autopsy performed".
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This has not been confirmed by Italian prosecutors.
Imane Fidal, 34, died of chronic organ failure two weeks ago after checking into hospital with severe stomach pains.
The former model first hit the headlines in 2012 when she gave detailed testimony about the goings on at Berlusconi's orgiastic parties at his villa in Arcore near Milan.
In October 2010, it emerged that Mr Berlusconi had called a police station asking for the release of a 17-year-old girl, Karima "Ruby" El Mahroug.
She was being held for theft and was also said to have attended his so-called "bunga-bunga" parties.
5 tips on how to keep you kidneys healthy
It's not easy to undo kidney damage and may require painstakingly tedious procedures like dialysis or a kidney transplant. Owonala said: "This year, the World Kidney Day campaign aims to achieve kidney health for everyone, everywhere ".
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