We are raiding the Guardian long read archives to bring you some classic pieces from years past, with new introductions from the authors. This week, from 2021: An intrepid expert with dozens of books to his name, Stéphane Bourgoin was a bestselling author, famous in France for having interviewed more than 70 notorious murderers. Then an anonymous collective began to investigate his past By Scott Sayare. Read by Simon Vance. Help support our independent journalism at theguardian.com/longreadpod