The Chairman of Bulgaria's Aikido Federation died in a crash near the village of Belokopitovo on Saturday.
The car, in which Ivaylo Draganov, 32 travelled, was moving at a high speed when smashed into a billboard.
The victim was on his way to the town of Shumen, where he should join an aikido examination board.
A woman has also been heavily injured in the accident. Her life is still in danger.
Darik News reporters and other media representatives, who arrived at the spot, were attacked by friends of the victim and the injured woman.
One of the aggressors hit a photographer and then came on the journalists' car, kicking its front door until it bended.
The reporters involved immediately went to the nearby police station, where they are still giving evidence to the accident.