The mystery surrounding the death of a Moroccan model who was due to testify against Silvio Berlusconi over his “bunga bunga” sex parties has deepened after no traces of radioactivity were found in her body.

Imane Fadil, 34, died in hospital in Milan earlier this month from massive organ failure after telling her brother and her lawyer that she feared she had been poisoned.

As a murder investigation was opened, there were reports that she may have been contaminated with radioactive substances.

Investigators were concerned enough to order doctors to be equipped with protective clothing when they subjected the body to examination this week.

But tests conducted on tissue samples from her kidneys and liver at the State University of Milan found no such evidence of radioactivity, prosecutors in Milan said.