A team of five Egyptian prosecutors and police has come to Rome with a 2,000-page file on Giulio Regeni, a 28-year-old PhD student at Cambridge University.
Their findings were being presented to Rome prosecutor Giuseppe Pignatone and senior security officials in a closed-doors meeting at a police training college.
Italian officials are not convinced everything is being done to bring Regeni's killer or killers to justice and have warned of consequences if the Egyptians do not present a credible account of everything they know about his gruesome fate.
The talks are expected to continue into Friday.
The case is a testing one for Italian Prime Minister Matteo Renzi, who has fostered a close relationship with Egypt's military-backed president, Abdel Fattah al-Sisi, but is under pressure to respond to public anger over the case.
"The relationship is a huge deal for Italy but Egypt has burnt most of its credit in the last two months in a not very smart way," said Mattia Toaldo, of the European Council on Foreign Relations (ECFR) in London.
Regeni disappeared in central Cairo on January 25.
His body was found on the outskirts of the city on February 3 bearing the signs of torture which, an autopsy concluded, had been inflicted over several days.
Media coverage of the case has focused international attention on other disappearances and rights abuses in Sisi's Egypt.
Regeni's family have threatened to release pictures of his mutilated body to keep the pressure on over his death, and their stance was praised Thursday by the mother of Khaled Said, whose 2010 killing by Egyptian police contributed to the wave of anger that led to the Arab spring uprising of 2011.
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"I thank you for standing with us and caring about torture cases in Egypt," Laila Marzouk said in a video posted on YouTube.
'Lies again and again'
Italian officials were initially told Regeni had been killed in a car accident, then that his death had been linked to a personal dispute.
At the end of last month, Egypt publicly announced police had killed four members of a criminal gang they suspected of murdering Regeni.
That version of events was greeted with outraged scepticism in Italy, where many suspect the murder was the work of elements in the security services -- a theory Cairo dismisses as without foundation.
Foreign Minister Paolo Gentiloni told parliament on Tuesday that Italy was preparing "immediate and proportionate" action if the Egyptian delegation did not provide satisfactory answers.
"Basically he is saying to Sisi: 'You told us lies again and again, and now we have to do something'," Toaldo said.
Italy's investigators are still waiting to receive Regeni's mobile phone records and CCTV images from the neighbourhood in which he was abducted.
Rome also wants to know if and why Regeni was under surveillance prior to his abduction. The student had been researching independent labour unions in Egypt.
Toalda said Italy's options in terms of action were limited to recalling its ambassador, warning its citizens against travel to Egypt on security grounds or seeking backing from its European Union partners to put pressure on Cairo over the case.
All are problematic. An ambassador call-back risks being seen domestically as purely symbolic while a travel ban would hurt Egypt's battered tourism industry at the cost of escalating the rift with Sisi's government.
And other EU countries might not be keen to jeopardise their relations with Egypt to support Italy given Rome's past courting of the Sisi regime.