The suspect, who is also believed to have been involved in the foiled attack on a high-speed train in August 2015, is still being actively searched by police.
Known only by his Islamic State alias Abou Walid, the suspect is said to have had close ties to Abdelhamid Abaaoud, the mastermind of the Paris attacks who was killed killed in a police raid shortly after the massacre.
A judicial source told France Inter radio the suspect appears to have “vanished into thin air” and that the jihadist’s current whereabouts “remain unknown”.
The insider said: “Abou Walid is the person who is thought to have driven Mr Abaaoud to Brussels in August 2015. Mr Abaaoud had just returned from Syria to plan the Paris attacks, which were successfully launched three months later.”
French police also believe that Abou Walid, whose true identity remains a mystery, also played a key logistics role in the failed attack on a Thalys train from Amsterdam to Paris in August 2015, which was prevented after four passengers helped overpower the alleged would-be gunman, Ayoub el-Khazzani, a 28-year-old Moroccan national who is currently awaiting trial.
Abou Walid is said to have driven Mr el-Khazzani to the Brussels train station where he boarded the Thalys train.
Valid is also believed to have supplied Mr el-Khazzani with the weapons used in the attack, while it is reported he packed the alleged attacker’s travel bag.
The judicial source added that Mr el-Khazzani had told investigative magistrates that the man known as Abou Walid is “a Belgian national of Turkish origin who is in his mid-twenties”.
The insider added: “He speaks French and at least one other language – either Flemish or German.”