Imane Fadil
© OLIVIER MORIN/AFP/Getty ImagesModel Imane Fadil pictured at Milan's court during the trial of the former Italian prime minister Silvio Berlusconi for allegedly having sex with an underage prostitute on April 16, 2012.
An investigation has been launched into the death of a model who was a key witness in the trial of former Italian Prime Minister Silvio Berlusconi, and his so-called "bunga bunga" sex parties.

Moroccan model Iman Fadil, 33, died on 1 March at a hospital in the Italian city of Milan, BBC News reported, citing the Italian media.

The model had been hospitalized for a month before she passed away, after suffering from stomach pains. Fadil claimed to her friends and lawyer that she was poisoned, according to Reuters. Her death was revealed on Friday.

Milan chief prosecutor Francesco Greco said she showed "symptoms of poisoning," the Associated Press reported citing the Italian news agency ANSA.

Fadil's medical records contained "several anomalies," Greco told Reuters.

"The doctors have not identified with any certainty any pathology which can explain the death," he said.

Addressing Fadil's death on Saturday, Berlusconi said, according to BBC News: "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."

The 82-year-old former premier has had a career of extremities, which has seen him lead four governments as the head of the Forza Italia (or Go Italy) party and be dogged by sex and money scandals.

In 2012, Fadil testified against Berlusconi after he was accused of paying for an underage prostitute. Berlusconi was convicted, but subsequently acquitted in 2015.

Speaking in court at the time, Fadil claimed Berlusconi held raunchy parties at his home. One saw women dressed like nuns stripping and pole dancing, while another featured a woman stripping for the politician while wearing a mask of the soccer player Ronaldinho, Fadil said.

"They started to dance like the nuns of the film Sister Act, and then they took off their clothes," she claimed, referring to the 1992 movie starring Whoopi Goldberg.

That year, Fadil told prosecutors she was offered money not to speak in court. At the time, she told press she feared for her life for speaking out, the Associated Press reported.

Berlusconi is among defendants currently facing charges for giving women at the parties hush money ahead of the 2012 trial. The accused deny the allegations.

In 2013, Berlusconi was found guilty of financial fraud and tax evasion, and handed a four-year prison sentence.