A murder investigation is under way in Italy after the death of a Moroccan model who testified against former PM Silvio Berlusconi in 2012.
Imane Fadil, 33, died on 1 March in a Milan hospital, a month after being admitted with stomach pains. At the time she said she had been poisoned.
Italian media say she may have been poisoned with a radioactive substance.
She was a key witness against Mr Berlusconi, who was accused of paying for sex with an underage prostitute.
Mr Berlusconi, 82, was initially convicted but then acquitted on appeal. He was later convicted of tax fraud and sentenced to carry out community service.
Speaking on Saturday, Mr Berlusconi said: "It's always a pity when a young person dies. I never met this person, never talked to her.
"What I read of her statements made me think that everything was invented, absurd," he said.
Mr Berlusconi - who has served as prime minister in four governments - is still facing a number of charges, including bribery.
He denies the allegations.
What about the murder investigation?
Milan chief prosecutor Francesco Greco told Reuters news agency there were "several anomalies" in Ms Fadil's medical records.
"The doctors have not identified with any certainty any pathology which can explain the death," he said.
Italy's Corriere della Sera newspaper reported that Milan's hospital had sent samples to a specialist laboratory.
The results suggested the presence of a mix of radioactive substances, including cobalt.
This has not been confirmed by Italian prosecutors.
Italian media also report that Ms Fadil - a regular guest at Mr Berlusconi's sex parties - was writing a book about her experiences, and magistrates investigating her death have obtained a copy of the manuscript.
Mr Berlusconi's reputation was tarnished by allegations about the parties at his private villa.
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.
In June 2013 he was found guilty of paying her for sex, and of abuse of power. The case was eventually overturned in 2014.
Mr Berlusconi has always maintained he is "no saint" but firmly rejects claims he has ever paid for sex with a woman, saying: "I never understood where the satisfaction is when you're missing the pleasure of conquest."