One of the Brussels suicide bombers has been identified as a former ISIS prison guard by a former French hostage in Syria.
Najim Laachraoui, 24, blew himself up at Brussels airport on March 22 in a carefully choreographed ISIS attack in which 32 people were killed at the airport and a metro station in the city.
Laachraoui, a Belgian national, has now been identified as Abou Idriss, one of several men who guarded them in an ISIS prison camp in Syria between 2013 and 2014.
French journalist, Nicolas Henin, was freed in April 2014 and his lawyer Marie-Laure Ingouf confirmed reports in French newspapers that her client had identified Laachraoui.
Belgian prosecutors have said Laachraoui travelled to Syria in February 2013 to join up with ISIS.
He remained off the radar of until September 2015 when he was registered under a false name at the border between Austria and Hungary.
Prosecutors have also linked Laachraoui to November's attacks in Paris in which 130 people died.
They said his DNA was found on a suicide vest and a piece of cloth at the Bataclan concert hall where 90 people were killed.
Police also found his DNA on explosives used at the Stade de France, leading investigators to believe he made the bomb used in both attacks.
Laachraoui was publicly identified as a suspect in the Paris attacks for the first time on March 21, only hours before the Brussels attacks. It is thought his unmasking may have forced him to bring forward the attacks.
Najim Laachraoui (left) seen with fellow suicide bomber Ibrahim El Bakraoui at Brussels airport shortly before they detonated suicide bombs on March 22. The so-called 'man in the hat', Mohamed Abrini, right, has since been arrested but has played down his role
In its own magazine, Dabiq, ISIS admitted Laachraoui was Abou Idriss and was a key player in both the Paris and Brussels attacks.
The French hostages previously identified Mehdi Nemmouche as one of their ISIS guards. Nemmouche is awaiting trial for killing four people in an attack on the Jewish museum in Brussels in 2014.
A third ISIS guard has been identified as Salim Benghalem, a French national, who is on the run. He has been sentenced in absentia in France for recruiting for ISIS and has been listed as a 'foreign terrorist combatant' by the US.