Najim Laachraoui
Najim Laachraoui seen in this undated photo issued by the Belgian Federal police. Reuters

One of the suicide bombers responsible for the attack on Brussels airport guarded four French journalists who were held hostage by Islamic State in Syria. At the time he was guarding them bomber Najim Laachraoui was known as Abou Idriss, a lawyer for two of the hostages told French media.

The four were freed in 2014. Five US and UK hostages, and two Japanese were subsequently beheaded by Islamic State. Over 30 people were killed when Laachraoui and brothers Ibrahim and Khalid El Bakraoui detonated suicide vests in the airport and a metro station in the city.

Laachraoui, a 24-year-old Belgian national, is believed to be responsible for making the bombs used in the attacks, as well as those used in the 13 November Paris attacks, in which 130 people were killed. The lawyers said their clients recognised Laachraoui from photographs published after the Brussels attacks.

They had earlier identified Mehdi Nemmouche, who killed four people in an attack on a Jewish museum in Brussels in May 2014, as another of their jailers. Nemnouche is now in Belgian custody.

The four men – Didier Francois, Pierre Torres, Edouard Elias and Nicolas Henin – spent 10 months in Isis captivity after being captured in June 2013.