For four decades, the mystery linked to the death of Grégory Villemin, found drowned in Vologne a few kilometers from his home in the Vosges department, has regularly made the headlines. 40 years of chaotic investigation have left unsolved the mystery of the murder on October 16, 1984 of “little Grégory”, which continues to arouse interest and fascination in France. A look back at one of the most followed legal cases of the last forty years with Patricia Tourancheau, journalist specializing in criminal affairs and author of the well-documented book “ The complete story of the Grégory affair », Points editions.