The murdered Cambridge student whose battered body was found in Cairo was killed because Egypt's secret service believed that he was a spy, Italian media claims.

Giulio Regeni, 28, was found dead near a highway outside the Egyptian capital, nine days after he was reported missing, having suffered 'inhuman animal-like violence'.

An autopsy carried out in Italy following his corpse's repatriation found that the PhD student had been brutally tortured before his death, including having his finger and toe nails pulled out.

Murdered: Cambridge graduate student Giulio Regeni, 28, from Italy, was subjected to 'animal-like' torture before his death in Cairo, Egypt, including his killers pulling out his finger and toenails

Italian media are now pointing fingers at Egyptian security services, saying the autopsy results show signs of torture which suggests that his killers believed that he was a spy, The Local reports.

The autopsy revealed that Mr Regeni's neck was twisted or struck which broke a vertebra and left him unable to breathe.

Prosecutors from Rome have now opened a murder investigation into the death of the doctoral student and ministers are calling for Egypt's president Abdel Fattah el-Sisi to fully cooperate.

Egyptian Interior Minister Magdi Abdel Ghaffar has responded to the accusations in Italian media, completely rejecting any notion that seucrity forces were involved in the killing of Mr Regeni.

'There are many rumours repeated on pages of newspapers insinuating the security forces might be behind the accident. This is unacceptable. This is not our policy,' he told a news conference.

Prime Minister Matteo Renzi is under pressure to authorize a state funeral for Mr Regeni, with anger mounting in Italy over Egypt's initial claims that the student had been killed in a road accident.

Mr Regeni, a student of Cambridge's Department of Politics and International Studies, had been in Cairo for just a few months, as part of his Ph.D. research into Egyptian labor movements, when he disappeared on January 25.

Murdered: The body of Mr Regeni was found on naked from the waist down on the side of a Cairo highway, bearing signs of torture, including stab wounds and cigarette burns according to an Egyptian investigator

He had left his apartment with a plan to travel by subway to meet a friend in the city, but was never seen again.

A second autopsy in Italy has shed further light into Mr Regeni's death with details so shocking that interior minister Angelino Alfano told Sky TV that he struggled to catch his breath after reading the report.

While opening details have been released analysis of tissue and body fluid, which could help pinpoint or at least narrow the time frame when Mr Regeni died, are expected to take several days.

Mr Alfano said the student had suffered 'something inhuman, animal-like, an unacceptable violence.'

Prosecutor Ahmed Nagi, who leads the investigation team on the case, had previously said 'all of his body, including his face' had bruises, cuts from stabbings and burns from cigarettes, adding that it appeared to have been a 'slow death.'

Italian police were dispatched to Cairo on Saturday and have started working with their Egyptian counterparts on the case.

Mr Alfano said: 'I am convinced that it is in the interest of el-Sissi to work together. No one can bring Giulio back to life, but bring the truth to the surface will perhaps be able to save more lives.'

Demonstrations: On the day Mr Regeni went missing, residents took to the streets to mark the fifth anniversary of the Arab Spring. Pictured, supporters of ousted President Mohamed Morsi march in Cairo

An Egyptian friend of Mr Regeni, who was from Fiumicello in the north-east of Italy, said that shortly before his death the student had been seeking contacts for trade union activists to interview as part of his research.

This political research had been the main focus when the friend was questioned by police following the Italian student's disappearance, he said.

Another friend explained he was travelling to downtown Cairo on the day of his disappearance, he said: 'A friend called him after he didn't show up. His cell was off then,' he told MailOnline, speaking on condition of anonymity.

He added: 'We briefly talked on the day of his disappearance, about two hours earlier. He was happy and cheerful, he was about to meet a friend. No indication of any worries whatsoever.

'I just feel terrible for his family, his girlfriend and all his friends.'

The Egyptian authorities had intensified a crackdown on dissent ahead of the January 25 anniversary of the Arab Spring, with police raiding apartments in downtown Cairo seeking signs of plans for organised protests and checking people's social media accounts.

For years, rights groups have accused Egyptian police of regularly torturing detainees.

Over the past year, they have also accused them of using 'forced disappearances' - detaining suspected activists or Islamists in secret without reporting their arrest.

The Egyptian Association for Rights and Freedoms documented 314 such disappearances in 2015, according to a lawyer, Halem Henish.

Most later turned up in prison, but at least five were found at the morgue, including one with signs of torture like burns and electric shocks.