In a statement issued on Monday prosecutor Olivier Elsig said: “At the end of a dense and complex investigation the exact cause of this tragedy could not be determined. However, all possible causes, for example illness or inattention, relate to the dead driver, all other hypotheses having been dismissed.”
The Belgian schoolchildren and their teachers were returning from a skiing holiday in the Val d’Anniviers on March 13th 2012 when their coach crashed into a wall of a motorway tunnel near Sierre, killing 28 people including the driver.
The statement comes just two days before a Dutch investigative firm is due to reconstruct the crash at the request of a group of parents of the victims.
A bus driver will drive on an identical path as the coach in the accident with 3D cameras recording his movements.
To date, the conclusions of Swiss investigators have not satisfied parents of the victims, who believe that the driver of the coach may have committed suicide.