Italy has condemned Egypt’s decision to rule out charging five state security officers over the torture and murder of an Italian student near Cairo.
Earlier this year Italian prosecutors named four suspects believed to be behind the death of Giulio Regeni.
But this week Egypt’s public prosecutors said there was insufficient evidence against the group.
Egyptian authorities have previously denied that any of their officials were involved in Regeni’s kidnap and murder.
They have suggested other explanations – including that he was the victim of a robbery by a criminal gang, or a gay crime of passion. Italian officials have dismissed these theories.
Mr Regeni, a Cambridge University student, had been researching independent trade unions, a sensitive issue in Egypt.
His murder has caused a diplomatic row, with Italian prosecutors accusing Egyptian officials of trying to mislead the investigation.
Earlier this year, Egypt’s public prosecutor said it was “temporarily closing” its investigation, with Mr Regeni’s killer “still unknown”.