The search for the truth about the brutal killing of Giulio Regeni, the 28-year old Italian researcher found dead in a ditch in the outskirts of Cairo two months ago, is turning into one of the most delicate diplomatic cases Italy has dealt with recently. It is also putting to a hard test the credibility of the Italian government.

Italian and Egyptian prosecutors are expected to meet in Rome on Thursday in what the Minister of Foreign Affairs, Paolo Gentiloni, described as a crucial meeting to reach a solution to the case. Gentiloni warned the Egyptians that Italy's patience was running out.

"Unless there is a change of pace [by Egypt], Italy is ready to react by adopting immediate and proportional measures," Gentiloni said on Tuesday, in what sounded like a direct threat to Cairo.

The stormy exchange of statements between Rome and Cairo, the unproductive string of visits and documents between the investigative teams as well as the Egyptian authorities' ever changing versions on how Regeni was murdered came to a climax on Tuesday when Gentiloni issued his strongest statement since the start of the case.

"We will not let Italy's dignity be trampled on," he said, addressing the Italian Senate.

"We are at a turning point. We are not sure how much closer to the truth we'll get, but the decision to send the prosecutor and police officials to Rome on Thursday marks a change of direction by the Egyptian side," said Stefano Stefanini, columnist at the daily La Stampa and a former diplomat.

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Regeni's death, according to analysts, has turned into an issue of national pride that the Italian government can no longer afford to neglect.

Italy can take a series of significant diplomatic measures, like recalling its Ambassador, discouraging researchers and students from going to Egypt, or issuing a travel ban. Paolo Valentino, an editorial of Il Corriere

The indignation of the Italian public opinion has been growing proportionally to the inability - or unwillingness - of the Egyptian authorities to provide answers to the Italian prosecutors investigating the case.

The shocking details about the torture, and the week-long ordeal suffered by the Italian student, sparked public outrage and disgust, prompting spontaneous protest campaigns throughout Italy that are not yet abating.

Regeni, a Cambridge student, went missing on the evening of January 25, on the fifth anniversary of the 2011 popular uprising, as security forces were raiding Cairo's landmarks in an attempt to abort possible protests.

Regeni's body, half-naked and mutilated, was found a week later on the desert road between Cairo and Alexandria. Human rights organisations said the burns and wounds on the Italian were consistent with the methods of torture used by Egyptian security services to repress the opposition.

However, the Egyptian authorities have always denied the involvement of its security officers and never questioned them. For weeks the public prosecutor and investigators shared as little information as possible with their Italian counterparts, while the interior ministry started offering different versions of the story.

The first was that the researcher had been killed by drug dealers; another version stated that the killing had occurred within Regeni's research field, the Egyptian unions; a week ago, Egyptian police claimed they had killed Regeni's kidnappers, apparently common burglars, in a shootout and found his bag with all his documents.

All versions presented blatant inconsistencies that were promptly rejected by the Italian authorities as attempts to provide a "convenient truth".

"The truth might be uncomfortable, but we cannot ignore it," Stefanini said.

"Italy, not only Regeni's family, deserves the truth, while Egypt cannot lose its face. The dialogue starting in Rome is based on this delicate balance. The justice that Italy asks for won't happen through the humiliation of Egypt."

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Italy, according to its foreign minister, was still expecting to receive key information that the Egyptians have refused to share so far, including data on Regeni's phone traffic and video of the underground metro stations in the area from where the student allegedly disappeared.

If the Egyptian delegation failed - in the expected meeting on Thursday - to present these two important chapters of the dossier, dialogue between the two sides will be - most likely - seriously compromised and it will be difficult for the Italian investigators to ever reach the truth.

So far Rome had put up with the lack of cooperation and shunned a more aggressive tone in an attempt to prevent a breaking point.

But the constant diplomatic pressure, while helping the dismissal of improbable versions on the death of Regeni, hasn't brought the prosecutors closer to the truth.

"We expect a strong reaction by the Italian government," said Regeni's parents, who had earlier set the deadline of April 5 to demand a "final word on the case".

But how far Italy is willing to go in a case that has already strained relations between the two countries, remains to be seen. "Italy can take a series of significant diplomatic measures, like recalling its Ambassador, discouraging researchers and students from going to Egypt, or issuing a travel ban," Paolo Valentino, an editor of Il Corriere explained.

Other measures might include a downgrading of diplomatic ties, a cancellation of the intergovernmental meetings that were agreed upon by Italian Prime Minister Matteo Renzi and President Abdel Fattah el-Sisi in 2014.

"However nobody would like to invoke economic measures. It is difficult to think of a possible embargo that would compromise Italy's role as second commercial partner of Egypt after Germany," Valentino added.

Italy has strong economic interests in the Arab country, where last year the state-owned Italian oil company ENI discovered a giant offshore gas field that might be the largest in the Mediterranean.

Economic ties are not the only ones at stake. Egypt is deeply involved in Libya, where Italy is supporting a strong diplomatic push for the creation of a national unity government supported by all factions.

Egypt is a negotiating partner in stabilising a region that poses huge security challenges to Italy and Europe alike.