It seems that the headless corpse found at Saige would not have been the victim of a brutal and violent murder.
Instead it transpires that the history would be of two motorcyclists who had a well-watered evening at the Foire de Bordeaux before heading home. On the way one motorcyclist would have fallen off the back of the bike and would have been dragged along the road, killing him and removing one arm and half his head (grim, eh?) When the surviving motorcyclist would have realised what happened he would have called the police.
The surviving motorcyclist is in police custody.
(Newspapers in France write of alleged events in the conditional mood.)