The alibis of all identified suspects hold up, but one last unknown remains: the identity of the motorcyclist whom all witnesses claim to have seen near the scene of the massacre on the day it happened. The investigators' latest theory revolves around this motorcyclist. He might be the killer. And if he isn't, he must have either seen the perpetrator or be protecting him. A composite sketch is circulating. The man is being tracked by police forces across France and England. After searching every motorcycle helmet store (witnesses described a very distinctive helmet that was only produced in limited quantities) and scrutinizing all phone records of devices that connected to the area on the day of the massacre, the gendarmerie finally identifies the motorcyclist. His interrogation in police custody leads to astonishing twists.