The National Anti-Terrorism Prosecutor's Office (PNAT) has initiated an investigation following the arrest of four men in northern France, who are accused of conspiracy to commit terrorism and illegal possession of firearms. The identities of the detainees have not yet been disclosed, but law enforcement seized a pistol, a bottle of hydrochloric acid, and an Islamic State (ISIS) flag from the vehicle they were traveling in, which was found near the Longuenesse prison. Reports indicate that police also discovered materials for explosive fabrication in the vehicle, raising suspicions that the individuals were preparing a potential 'selective attack' against the prison and possibly had connections with inmates inside.

The arrests occurred shortly after a warning about a drone flying over the prison early on Tuesday morning, prompting a swift police response. According to the police union CGT, the situation was deemed serious enough to warrant immediate intervention from the National Anti-Terrorism Prosecutor's Office, which highlights the ongoing threat of terrorism in France, particularly concerning prison facilities where radicalized individuals may be communicating with the outside world.

This incident underscores not only the challenges law enforcement faces in preventing terrorist activities but also the need for robust security measures around sensitive locations like prisons. The link to ISIS adds another layer of complexity to the investigation, as authorities will need to explore the extent of these individuals' connections to terrorist networks to fully understand the potential risks involved.