Police have found the DNA of Najim Laachraoui, an accomplice in the Paris attacks, on explosives used by the jihadists during the assault, a source close to the French investigation said Monday.

The 24-year-old, who left for Syria in February 2013, is known to have returned to Europe using false documents in September, travelling with Paris attacker Saleh Abdeslam who was captured by police in Brussels on Friday.