Thai authorities are seeking an arrest warrant for an heir to the Red Bull energy drink fortune after he failed to appear for his indictment in the hit-and-run death of a policeman, a prosecutor said Monday.

A lawyer for Vorayuth Yoovidhya said the 30-year-old heir was on a business trip in Singapore and was unable to return to Thailand for the indictment because he fell ill.

His absence means a speeding charge will be dropped because the statute of limitations expires Tuesday. He still faces charges of causing death by reckless driving and not stopping to help, which carry a maximum sentence of 10 years.

Prosecutor Ruecha Krairiksh said Vorayuth showed an intention to flee by not appearing for the indictment.

"Prosecutors have discussed and decided that the defendant appeared to be fleeing and we will oppose his bail request during the trial process," Ruecha said.

It is the sixth time Vorayuth's indictment has been postponed since he allegedly slammed his Ferrari into a police officer at high speed and dragged his body down a Bangkok street last September. Police traced oil streaks to his family's estate in a nearby wealthy neighborhood, but a local police superintendent initially attempted to cover up the heir's involvement by arresting a bogus suspect.

The case created an uproar among Thais because of the widespread perception that the rich and well-connected enjoy impunity from punishment for wrongdoing.

Defense lawyer Thanit Buakeaw said Vorayuth left Thailand on Thursday and came down with influenza in Singapore. He showed reporters a medical certificate issued by a Singapore clinic on Sunday that said Vorayuth was "unwell" and was advised to rest for one or two days.

"[He] has no intention or cause to flee but he really can't be here today because he became suddenly ill," the defense lawyer said.

Dr. Neo Wee Suan, who issued the medical certificate, told The Associated Press by telephone that he could not confirm whether he treated Vorayuth because of patient confidentiality.

Vorayuth is the grandson of Red Bull creator Chaleo Yoovidhya, who died in March last year. The family was ranked fourth richest in Thailand this year by Forbes magazine with a net worth of $7.8 billion.

The family also co-owns the sole authorized importer of Ferrari cars in Thailand.

The family paid 3 million baht [$93,100] to the dead policeman's siblings in a deal aimed at avoiding a civil lawsuit.