The relatives of Frédérik Gagné reported his disappearance on December 19, they had not heard from them for two days. A few days later, the disappearance investigation turned into a murder investigation.
The notice of disappearance of the 32-year-old man from Thetford Mines was sent to the media on December 20. Already, the file was in the hands of the Service for the investigation of crimes against the person of the Sûreté du Québec since the day before, it was already suspected that a criminal act had been committed.