Bangkok, Thailand (CNN) -- Thai police added a drunken driving charge against a Red Bull energy drink heir accused of ramming a police officer with his Ferrari and fleeing the scene, authorities said Friday.
Authorities charged the drink creator's grandson with negligent death and hit-and-run after the crash.
They said he had a high alcohol content, an additional charge that if found guilty, would add up to 10 years to his sentence, according to Police Maj. Gen. Anuchai Lekbumrung.
CNN attempts to reach the suspect's attorney were unsuccessful.
The arrest of Vorayud Yoovidhaya -- a member of one of Thailand's richest families -- has sparked a controversy over the nation's justice system.
At first, police allegedly tried to cover up the 27-year-old's involvement by arresting a suspect who pretended to be driving the car at the time. The arrest of the bogus suspect led to the suspension of a police officer.
The officer killed in the crash, Police Sgt. Major Wichien Klanprasert, was responding to a robbery call when his motorcycle was hit by what a witness described as a black sports car early Monday, authorities said.
His cremation is planned for Friday evening, relatives said.
Investigators said they followed the path of leaked oil from the crash scene to the suspect's home.
Police entered his mansion with a search warrant and found his Ferrari, which was wrecked on the front and had deployed air bags, authorities said.
The heir has admitted driving the car and hitting the motorcycle, but he claimed he was suddenly cut off by the bike, according to Lekbumrung.
He was charged with hit-and-run and causing a death with negligence, and was released on a bond of 500,000 baht (About $16,000).
An investigation is under way to determine how fast he was driving, police said.
The suspect's grandfather, Chaleo Yoovidhaya, teamed with an Austrian businessman to create the Red Bull brand and products. His father, Chalerm Yoovidhaya, is an executive with the energy drink company.
His father has attended evening services for the officer at the local temple, said Natthanan Klanpraert, the victim's sister-in-law.
The suspect and his mother also stopped by the temple Thursday afternoon, but the victim's family was not around, she said.