Chekatt was born in Strasbourg in February 1989, into a family with Moroccan roots, and appears to have fallen first into petty crime then gangster circles. The final stage, his apparent move into Islamic extremism, was reportedly sparked – or at least strengthened – during a spell in prison between 2013 and 2015.

Like many youths growing up on outer-city housing projects in France, home to many of the country’s north African immigrant population, where poverty and unemployment are rife, Chekatt left school early and had a series of low-paid jobs.

By the age of 29 he had 27 convictions for theft and violence, the public prosecutor Rémy Heitz said. On the morning of the Strasbourg attack, he was to have been arrested in connection with attempted murder linked to an armed robbery that went wrong last summer.

His religious practice and proselytising in jail were described by Heitz as “showing signs of radicalisation”. For that he was put on the Fiché-S list.

In 2016 Chekatt was added to the more specific Fichier des Signalements pour la prévention et la radicalisation à caractère terroriste (file of reports of the prevention and radicalisation of a terrorist nature), a little-known list of 20,000 people known to have been, or at risk of being, radicalised.

Five of his alleged accomplices were picked up in raids on Tuesday morning, but when police turned up at his apartment in a block at the Les Poteries district of west Strasbourg, Chekatt was not there. Inside, they found a stun grenade, a long rifle with ammunition and four knives, including two hunting knives.

Day  later (13.12.2018) the shooter was shot dead by the BST (specialised field brigade) in Strasbourg, rue du Lazaret in Neudorf. He had a handgun and a knife on him. He have pointed a gun at the police officers.