When Giulio Regeni's mutilated body was found in a ditch near Cairo in February 2016, it was so badly disfigured that his mother struggled to identify him.

Five years on, four members of Egypt's security forces go on trial in absentia on Thursday, accused of kidnapping the student, torturing him and killing him.

The Egyptian authorities reject the Italian allegations.

Regeni's parents will attend the trial in Rome, trying to find out what led to his death.

The 28-year-old student was abducted on 25 January 2016 while carrying out research for his PhD at Cambridge on Egypt's independent trade unions. A week later his body was discovered on the road to Alexandria.

Egyptian authorities constantly hindered the Italian prosecution, inventing wild stories behind the murder: a failed drug deal, a botched robbery, even a gay crime of passion.

But Italian prosecutors concluded that the Egyptian national security agency was behind the murder.