Three activists claimed they have evidence to prove that Vorayuth "Boss" Yoovidhya had illicit chemical substances, including cocaine, in his system during his Sept 3, 2012, fatal hit-and-run.
Veera Somkwamkid, secretary-general of the People's Network Against Corruption; Anon Nampa, a human rights activist lawyer; and Taejing Siripanich, secretary-general of the Don't Drive Drunk Foundation, posted on their Facebook pages that the evidence was never included in the police investigation file.
All three referred to what looked like copy of a letter by Vichan Peonim, head of the Forensic Pathology programme at Mahidol University's Faculty of Medicine at Ramathibodi Hospital, made to the head of the faculty's Department of Pathology.
The letter, dated Oct 1, 2012, was "about the substances found in the body of Mr Vorayuth Yoovidhya as requested by the Thong Lor Police Station". The letter showed that Mr Vorayuth's body contained Alprazolam, Benzoylecgonine, Cocaethylene and caffeine.
Alprazolam, commonly sold under the brand name Xanax, is used to manage anxiety disorders. The drug is classified as a Type 4 stimulant, and it is highly regulated in the kingdom, the letter said. Alprazolam residues can normally be detected in urine from one to five days after the drug is consumed, it said.
It said Benzoylecgonine is the main metabolite found in cocaine, which can still be detected in blood for as long as 28 hours after ingestion.
Cocaethylene is a substance formed when cocaine is mixed with alcohol, it added.
