On 1 April, their train was approaching the gare d'Ascq, a junction where three railroads intersected, when an explosion blew the line apart, causing two cars to derail.

The commander of the convoy, SS Obersturmführer Walter Hauck, ordered troops to search and arrest all male members of the houses on both sides of the track.

Six more men were arrested and charged with the bomb attack after an investigation by the Gestapo; they were eventually ordered to be executed by firing squad.

The Oberfeldkommandant of Lille justified the massacre, stating:The population must know that any attack on German units or individual soldiers will be responded to by all means required by the situation.

After the massacre, 60,000 workers started a strike in Lille — one of the most important demonstrations in France during World War II under German occupation.