Brussels - Belgian authorities opened a manslaughter inquiry on Monday two days after the death of French racing driver Anthoine Hubert in a Formula Two race.
It is standard practice in Belgium to launch a probe into "accidental homicide by person unknown" after any fatal road accident, and does not in itself imply criminal charges are likely.
The 22-year-old was killed on Saturday in a crash on the Spa-Francorchamps circuit.
Hubert's Formula Two race was cancelled, but the Belgian Formula One Grand Prix went ahead on Sunday.
"For the moment, there's nothing to suggest any negligence, but that will be for the experts to determine," said magistrate Gilles de Villers Grand Champs, of the Verviers prosecutor's office.
Several road safety and auto racing experts have been recruited to advise the inquiry.
"From the point where someone had died and the police had made a report, it was necessary for the competent prosecutor to open an objective investigation," the magistrate said.
At the beginning of the second lap of Saturday's race, Hubert was involved in a high-speed collision with US driver Juan Manuel Correa, Frenchman Giuliano Alesi and Japan's Marino Sato.
Hubert died from his injuries while Correa was taken to hospital with broken legs and has not yet been questioned, according to the prosecutor.
Sato and Alesi, son of former F1 driver Jean Alesi, were unharmed.
The crash happened on one of the fastest parts of the Belgian circuit, the Raidillon, where the track rises abruptly after a descent.
Hubert was lying in eighth place in the Formula Two championship after 16 events, having won in Monaco in May and in France in June, in races held alongside Grand Prix events.