Metropolitan Police Bureau deputy commissioner Jarumporn Suramanee said results indicated that the Ferrari driven by Mr Vorayuth, grandson of Chaleo Yoovidhya, the founder of the popular Red Bull energy drink, hit the motorcycle rode by Pol Snr Sgt Maj Wichian Klanprasert from behind which caused the officer to be killed instantly after suffering a broken neck.
After the crash, the officer's body hit the car's windshield before falling to the road.
Autopsy results revealed his body was not dragged by the car on the road, Pol Maj Gen Jarumporn said. However, the car dragged the motorcycle for about 100 metres.
Pol Col Chumpol Phumphuang, chief of Thong Lor police station, said police were waiting for results of a blood alcohol test conducted on Mr Vorayuth.
Mr Vorayuth yesterday paid his respects and made an apology to the late police officer at a Bangkok temple.
The 27-year-old, clad in black clothes and glasses, was accompanied by his mother Daranee to Wat That Thong yesterday evening, where the funeral ceremony of Pol Snr Sgt Maj Wichian was being held.
He apologised to the police officer's relatives and sat down in front of the coffin holding the body of Pol Snr Sgt Maj Wichian where he paid his respects and apologised to the dead officer.
Mr Vorayuth's lawyer said his client had not been drinking before the accident, but instead imbibed alcohol after he hit the policeman with his car.
Senator Samak Chaowapanant, who is the lawyer of the Yoovidhya family, said Mr Vorayuth did not drink any alcohol in his residence on Sukhumvit Soi 53 in the early morning on Monday before he was involved in the crash on Sukhumvit Soi 47.
"Boss was very sad," the senator said, referring to Mr Vorayuth by his nickname. "I understand that after the crash and his surrender, Boss drank that night to relieve his tenseness ... but he did not drink before the incident happened."
Senator Samak said Mr Vorayuth drove home without stopping to check the body of Pol Snr Sgt Maj Wichian because he was shocked and afraid.