A Belgian bomb-maker — suspected of making the explosive devices used in the Paris attacks in November — has been identified as the second suicide bomber at Brussels Airport, according to local media.

Najim Laachraoui, 24, was originally believed to have fled the airport in a hat, after his suitcase bomb failed to detonate.

But Belgian media now say police sources have identified him as the second suicide bomber.

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Belgium’s federal prosecutor earlier confirmed brothers Ibrahim El Bakraoui, 29, and Khalid El Bakraoui, 27, were behind suicide attacks at Brussels Airport and on a metro train station that killed 31 people and wounded 270 others.

Ibrahim El Bakraoui blew himself up in the check-in hall of the airport while Khalid El Bakraoui attacked a train at Maelbeek station near European Union headquarters.

The fourth man, who escaped in a hat, is still on the run. His identity is yet to be confirmed.

Laachraoui had been the subject of an international arrest warrant since March 2014. However he had used a false name, Soufiane Kayal, to evade detection.

Belgian prosecutors said Laachraoui travelled to Syria in February 2013.

In September 2015, two months before the Paris attacks, he travelled across the Austria-Hungary border — again using the name Soufiane Kayal — with Salah Abdeslam, a key suspect in the Paris attacks who was arrested last week.

A third man also travelling with them, Mohamed Belkaid, was shot dead during last week’s raids.

Suitcase containing largest bomb failed to explode

Belgian investigators discovered Laachraoui’s true identity after the Paris attacks, and suspected he played a key role in making the explosive vests used in the Paris attacks.

Police said Laachraoui — using the alias — had rented an apartment in Auvelais, south of Brussels, where it is believed much of the planning was done for the Paris attacks.

His DNA was also found at an address on Rue Henri Berge at Schaarbeek, in Brussels, used by the terrorist cell. It is unclear whether this was the same apartment in Schaarbeek from where the three suspects left by taxi for the airport on Tuesday.

Police tipped off by the taxi-driver found suitcases abandoned by the bombers, which contained nails and chemicals used for bomb-making.

Investigators are yet to identify the third suspect at Brussels Airport, who is still on the run. They say his suitcase “contained the most important charge”, but failed to explode. It blew up only after bomb-detonation experts arrived, thereby avoiding a higher death toll.

One other suspect is still on the run. Mohamed Abrini, 31, is a Belgian of Moroccan heritage. He was a childhood friend of Salah Abdeslam and is believed to have played a support role in the preparations for the Paris attacks.

Interpol release images of Khalid (left) and Ibrahim (right) El Bakraoui – two Belgian brothers identified as suicide bombers.

He was caught on security camera at a petrol station in northern Paris, travelling with Salah Abdeslam in the same car used to transport the attackers to Paris two days later.

Belgian prosecutors last year said Abrini was driving the same Renault Clio car that was later used by the attackers in the French capital. An accompanying police poster at the time described him as “dangerous and probably armed”.

Abrini’s family later told authorities he was not in Paris on the night of the attacks and insisted he was innocent.

Belgian authorities have told local media Abrini travelled to Syria in 2015.

The night of the Paris shootings he was reportedly seen back in Brussels, at a bar in Molenbeek, with Ahmed Dahmani, also suspected of involvement in the group behind the attacks.

Belgian media reports said Dahmani travelled briefly last year to Syria, where his younger brother was killed.

– ABC