Italy's premier insisted Friday that his country's friendship with Egypt can only exist "if the truth emerges" about the death of an Italian doctoral student who was doing research in Cairo.

Premier Matteo Renzi, in remarks on Italian state radio on the day of slain student Giulio Regeni's funeral, kept up the political pressure on the Egyptian government to find and bring to justice whoever tortured and killed the young man.

Regeni had been living in Cairo for a few months to research Egyptian labor movements for his doctorate from Cambridge University. His body was found on Feb. 3, nine days after he disappeared while heading to a subway station.

In the victim's hometown of Fiumicello in northeastern Italy, friends streamed in from afar for a private funeral service Friday afternoon in a gym. Townspeople opened their homes, offering spare rooms and couches to mourners who couldn't find lodging in the small town. The media and authorities were excluded from the service, with the 1,000 chairs in the gym reserved for relatives and friends only. Those who couldn't fit inside huddled together under umbrellas in a light rain and followed the service through loudspeakers.

During the service, a young man read out words of gratitude composed by Regeni's mother for her son.  "The energy of your thinking remains in my heart: your thinking, to love, to understand, to build tolerance. Affectionately, Mama."

The 28-year-old student disappeared at the same time that Egyptian police and other security agents were out in force on Cairo's streets, determined to quickly quash any demonstrations to recall the anniversary of the country's uprising in 2011. His body was discovered along a road on Cairo's outskirts.

"It's a dramatic affair," Renzi said on the radio. `'I again express condolences to Giulio's family and I say that which we have told the Egyptians: `Friendship is a precious thing and it is possible only in truth."'

Italian state TV said, without citing sources, that Italian investigators have spoken to a witness who told them that two men, apparently plainclothes police, stopped Regeni and escorted him away as he walked from his apartment building to the subway.

Some of Regeni's friends in Cairo have also told Italian investigators that Regeni was unnerved in December when, as the only foreigner at a labor meeting in Cairo, someone took his photo and left.

Egyptian authorities initially blamed Regeni's death on a road accident. A second autopsy, done in Italy after his body arrived last week, determined that Regeni suffered a fatal fracture of a cervical vertebra, either from a strong blow to the neck or from a severe, forced, twisting of the neck. His hands, feet and other bones had multiple fractures and his face was heavily bruised, the autopsy found.

Italian news reports said his toenails and fingernails had been ripped off.

Laboratory results to determine when he died are expected to take a few more days.