Red Bull heir suspected in fatal hit-run

The grandson of the Thai founder of Red Bull is being questioned on the suspicion he struck and killed a policeman with his Ferrari.

A grandson of the creator of the Red Bull energy drink is suspected of driving the charcoal Ferrari that struck and killed a policeman and then dragged the officer's body down a Bangkok street in an early-morning hit-and-run accident, police say.

Police took Vorayuth Yoovidhya, believed to be in his late 20s, for questioning on Monday after tracing oil streaks for several blocks to his family's gated estate in a wealthy neighbourhood of the Thai capital.

Bangkok's top police official, Lt Gen Comronwit Toopgrajank, said he took charge of the investigation after a lower-ranking policeman initially tried to cover up the crime by turning in a bogus suspect.

Comronwit himself led a team of officers to search the compound of late Red Bull founder Chaleo Yoovidhaya, one of Thailand's wealthiest men before he passed away this year, and confiscated a dark grey Ferrari with a dented front bumper.

The victim, Sgt Maj Wichean Glanprasert, 47, was killed during a pre-dawn motorcycle patrol. Thai media reported that the car dragged the officer and his motorcycle for several dozen metres as it sped through the residential neighbourhood.

Comronwit said he suspended the police officer who attempted to subvert the investigation.

"A policeman is dead. I can't let this stand. If I let this case get away, I'd rather quit," he told reporters.

"I don't care how powerful they are. If I can't get the actual man in this case, I will resign."

The Yoovidhaya family was ranked the fourth richest in Thailand this year by Forbes magazine, with a net worth of $US5.4 billion ($A5.27 billion). Red Bull creator Chaleo Yoovidhaya died in his 80s in March, leaving his heirs a wide range of businesses, including shares in the globally popular energy drink brand, hospitals and real estate.

The family also co-owns a company that is a sole authorised importer of Ferrari cars in Thailand.