An air traffic controller was found lying in a pool of his own blood after being stabbed to death in the secure control tower at the French airport where he was working.
Police said the man was found at 8am yesterday in an office adjoining the control room floor of the tower at Basel-Mulhouse Airport.
The airport operates as a joint Swiss-French air hub in eastern France.
The man had been stabbed in the throat, lung and chest, police said.
They added that the murder took place in a secure zone, which is accessible only to personnel in possession of an official identity badge.
A spokesman for the French airport authority, Direction Generale de l'Aviation Civile, said the victim, who is yet to be named, was 34 years old.
The murder victim, who was married and a father of one, was the controller in overall charge of the tower.
The man was found on the tenth floor.
No suspects have been arrested and the murder weapon was not found at the scene.
The airport is not far from either the Swiss and German borders.