At a press conference, prosecutors said that there was no evidence of medical malpractice and they were “quite sure” that Moroccan-born Imane Fadil had died of marrow aplasia caused by acute hepatitis.
“There can be many causes that generated the pathology,” Francesco Greco, chief prosecutor in Milan, said.
As a result, the prosecutors requested that the investigation be closed.
Fadil was one of the main witnesses who testified at the 2012 trial of Berlusconi on charges of having sex with an underage prostitute at one of his infamous bunga-bunga parties.
The 82-year-old Berlusconi was eventually cleared of paying for sex with an underage prostitute, but convicted of tax fraud.
An investigation had been opened following Fadil’s sudden death on March 1, after being brought to hospital on January 29, complaining of unexplained stomach pains and exhibiting “symptoms of poisoning”.
Fadil’s death wasn’t announced until two weeks after she died.
According to Italian daily Corriera della Sera, toxicological exams run by a laboratory in Padua suggested the presence of unusual heavy metals in her body, as well as radioactive substances such as cobalt.
But tissue samples from the model’s kidney and liver were sent to specialists who said it was “increasingly unlikely” on the basis of initial tests that she had been contaminated by radioactive substances.
At the press conference on Wednesday, prosecutors played a recording of Fadil telling her lawyer on the phone she feared someone was trying to poison her shortly before she died.