The body of a missing Italian student was found with signs of torture, including multiple stab wounds and cigarette burns, by the side of a highway on the outskirts of the Egyptian capital, an investigating prosecutor told The Associated Press on Thursday.

Giulio Regeni, a 28-year-old graduate student conducting research in Egypt, went missing in Cairo on Jan. 25, the fifth anniversary of the uprising that toppled longtime autocrat Hosni Mubarak.

At the time, police were on high alert against any demonstrations marking the anniversary and in previous days had conducted sweeps in downtown Cairo, detaining some Egyptian activists, deporting foreigners whose visas had expired and searching apartments.

The cause of Regeni's death was not immediately known.

His disappearance and death came at a time when authorities and media close to the security services have often depicted foreigners as plotting against Egypt. At the same time, human rights groups have accused police of being behind the disappearances of Egyptian activists and suspected Islamists, a claim police have denied. Before Jan. 25, security officials said they had been gathering intelligence for months on young pro-democracy activists and foreigners.

Egypt is also battling an insurgency by militants who have sworn allegiance to the Islamic State group.

The militants are mainly active in the Sinai Peninsula but have carried out attacks in Cairo and other parts of the country, including kidnapping and beheading a Croatian oil worker last year and setting off a bomb outside the Italian Consulate in Cairo. Authorities often justify their crackdowns by pointing to the fight against militants, who have killed hundreds of policemen and soldiers the past two years.

Italy's Foreign Ministry called in the Egyptian ambassador over Regeni's death, seeking maximum cooperation in the investigation. It said Italy renewed a request for Italian experts to be included in the probe and for the body to be returned to Italy as soon as possible. The Egyptian Foreign Ministry said it was cooperating with Rome.

News of Regeni's death also prompted Italy's economic development minister, Federica Guidi, to cut short a visit to Cairo and return home. Guidi had been heading a delegation of 60 business people in Cairo, aimed at finding new areas of economic commerce and to help more Italian companies set up business in Egypt. Most of the delegation returned as well.

An Italian newspaper accused Egyptian security forces of being behind the killing.

"The strong suspicion is that Giulio Reggeni, the 28-year-old student who loved Egypt, was killed by Egypt... by the system, by the security apparatus of an uncertain Egypt of today," read a page-one commentary from Il Sole 24 Ore, a business daily.

Regeni's body was found Wednesday at 11:00 a.m. along the Cairo-Alexandria Road in the 6th of October suburb in western Cairo in an empty lot near an auditing company  and was positively identified by his Egyptian roommate, said the prosecutor, Ahmed Nagi, who leads the investigation team on the case.

Nagi said the cause of death was still under investigation but said "all of his body, including his face" had bruises, cuts from stabbings and burns from cigarettes. He said it appeared to have been a "slow death."

Another person with knowledge of the case told the AP that the body was "partially burned" and also said his body was found on the same highway. The person spoke on condition of anonymity because he was not authorized to speak to media. An employee at Cairo's central morgue confirmed that Regeni's body was brought there.

The deputy head of criminal investigations in Cairo's twin province of Giza, Alaa Azmi, said initial investigations showed Regeni was killed in a road accident. He said the body had cuts and bruises and the preliminary forensic report didn't mention burns.

"We have to wait for the full report by forensic experts. But what we know is that it is an accident," Azmi said.

After Regeni disappeared, his colleagues and friends launched an online campaign searching for him. His friends said online that he was heading to meet a friend near Tahrir Square, the birthplace of the 2011 uprising. They refused to speak to AP on Thursday.

The University of Cambridge lists Regeni as a student of its Department of Politics and International Studies.

Friends said Regeni was doing research on workers and labor rights, a sensitive topic in Egypt. Disgruntled workers were among the forces in the 2001 anti-Mubarak uprising, and authorities still wory over worker discontent.

Ennio Scridel, the mayor of Regeni's hometown of Fiumicello in northeastern Italy, said the town was `'destroyed" by the news of his death. The town of 5,000 declared Sunday a day of mourning.

"If you go into a bar, you see dark faces, silences, looks that let escape all the sadness of a small community like ours," Scridel told Sky Tg24. He described Regeni as "an extraordinary person, who comes from a good family."

Egypt has seen continual upheaval since Mubarak's ouster in 2011. President Abdel-Fattah el-Sissi was elected in 2014. The previous year, as military chief, he led the ouster of Islamist President Mohammed Morsi following massive protests against Morsi and the political domination by his Muslim Brotherhood.

Since Morsi's ouster, security forces have led a fierce crackdown on Islamists, killing hundreds and jailing thousands. Under el-Sissi, they have also clamped down on other dissent, imprisoning liberal, pro-democracy activists.

Egyptian authorities are deeply sensitive to media coverage of attacks on foreigners, for fear of affecting the vital sector of tourism, one of the major sources of foreign currency, struggling since 2011.

After the Oct. 31 crash of a Russian passenger jet leaving the beach resort of Sharm el-Sheikh. Russia, the United States and Britain said the plane was downed by a militant bomb, but Egypt has said so far there is no sign of that and that the investigation is still ongoing.

In September, eight Mexican tourists and four Egyptian guides were killed when security forces in a helicopter opened fire on their desert safari. The results of investigations into the attack have yet to be released. As in other cases, authorities clamped a media gag order to prevent reporting on the investigation.

Media and officials often warn that foreigners are seeking to stir up unrest or fund activists causing turmoil.

"It has become increasingly difficult and dangerous to conduct research," said Amy Austin Holmes, head of the Sociology unit at the American University in Cairo. She said she knew researchers who had been barred from entering Egypt or arrested.

"So, above and beyond the tragic death of this bright young person who was obviously very committed and passionate about his fieldwork in Egypt, I am worried about the chilling effect this may have on others who wish to conduct research here," she said.

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