A public prosecutor in Rome has placed five Egyptian security officials under investigation over the disappearance of an Italian postgraduate student.
Giulio Regeni, who was studying at Cambridge University, had been doing research for his doctorate in Cairo when he went missing in January 2016.
His mutilated body was discovered nine days later on the city's outskirts.
The topic he was looking into - independent trade unions - is politically controversial within Egypt.
In January, a prosecutor in Rome said his research was the sole reason for his death, but no one has ever been arrested for it.
Italian investigators have been co-operating with Egyptian authorities on the case, but the two have come into conflict over allegations of police involvement.
Four of the five named are senior members of Egypt's National Security Agency - including a general, two colonels and a major.
What happened to Regeni?
The Italian PhD student disappeared on a research trip on 25 January 2016 - the fifth anniversary of the start of the uprising against former President Hosni Mubarak, when there was a heavy police presence in Cairo.
Regeni's body was eventually discovered in a ditch by the side of a road on 3 February.
His mother told the Italian parliament that her son's body was so disfigured that she was only able to identify him using the tip of his nose.
An Italian post mortem revealed extensive injuries indicating torture, including markings apparently carved into his body.
What did Egypt say happened?
Egyptian authorities have given conflicting accounts of what happened.
Initially they suggested Regeni died in a traffic accident before later blaming a criminal gang, whom they said had all been killed later in a shootout.
The claim was later branded "implausible".
Egypt has denied accusations that Regeni died in custody. However, officials have admitted that the security services were monitoring him.
In April 2016 Italy withdrew its ambassador to Egypt over the case, but it later appointed another.
It has been working with Egyptian investigators since, but the pace of developments has been slow.
The student's parents have campaigned for justice since his death, and the case has been highlighted by international human rights groups.
What is the latest?
The two nations' public prosecutors reconvened to discuss the case on Wednesday, but according to reports the meeting failed to produce results.
Afterwards, Egypt's State Information Service released a statement saying that "charges should be based on evidence and not suspicions" after Italian prosecutors asked them to approve the naming of the men.
On Tuesday Italy began formally investigating the five suspects, who Italian media named as General Sabir Tareq, Colonel Ather Kamal, Major Magdi Abdlaal Sharif, Captain Osan Helmy and agent Mahmoud Najem.
Under Italian law, being put under official investigation is not the same as a charge, but implies they are suspects.
Italian authorities say they are investigating the men over the kidnap of Regeni, but did not name them in connection with the murder itself.
On Monday, reports in Italy suggested the country's Foreign Ministry had summoned the Egyptian ambassador over the case, warning of escalation.
Last week Italy's lower house of parliament said it was cutting all diplomatic ties with the country over the lack of progress.
Egyptian officials have not immediately issued a response about Tuesday's development.