Claims linking Michael Schumacher's devastating injuries to a GoPro camera he was wearing when he crashed have sent shares tumbling.
GoPro's value fell by up to 16% after a French journalist linked the head-mounted camera to brain injuries Schumacher suffered in the skiing accident, late last year.
Jean-Louis Moncet told Europe 1 radio station in France: "The problem for Michael was not the hit, but the mounting of the GoPro camera that he had on his helmet that injured his brain."
The claim sparked a sharp fall in GoPro's share price, with executives at the US firm scrambling to prepare to statement on the claim.
But Moncret was forced on the defensive by confusion about the source of his claim.
It was initially supposed Schumacher's son, Mick, had told him because Moncet cited the teenager when reporting related claims about Schumacher's recovery.
However, Moncret rebuffed the notion on Twitter by denying he and Mick had ever spoken at all - let alone about the potential role of a GoPro camera.
GoPro has shot to prominence in recent years by allowing users to capture eye-catching experiences in high-definition, with videos shot on the cameras regularly going viral online.