Italy prosecutors have opened an investigation into the possible poisoning death of a Moroccan model who was a key witness in the trial against ex-Premier Silvio Berlusconi over his infamous "bunga bunga" parties, AP reported.

Imane Fadil, 34, died March 1 at a Milan-area hospital, where she had been treated since Jan. 29 for exhibiting "symptoms of poisoning," Milan prosecutor Francesco Greco said, according to the Italian news agency ANSA.

Berlusconi was initially convicted of charges that he paid for sex with an underage woman at the sex-fueled "bunga bunga" parties, and used his influence to cover it up. He was ultimately acquitted by Italy's highest court in 2015.

Asked Saturday to comment, Berlusconi said he was always sorry when a young person dies.

But he added: "I've never known this person and never spoke to her. What I read were her declarations that made me always think these were always invented and absurd things."