Police officers have claimed that illicit chemical substances, including cocaine, found in Red Bull scion Vorayuth "Boss" Yoovidhya in the 2012 hit-and-run case were used for his dental treatment, according to a House committee.
The committee had on Thursday invited officials for questioning regarding the hit-and-run case.
Natchanon Srikokuea, spokesman of the committee, told a press briefing on Thursday the panel had questioned officers who handled the case as to why they did not press charges related to illicit drug use against Mr Vorayuth despite a positive blood test proving the use of narcotics.
The officers told the committee they did not press the charge because a dentist confirmed he had administered medicines which had cocaine as a component for dental treatment. When Mr Vorayuth drank alcohol, it mixed with the medicines which caused some chemical substances in the body to be released, Mr Natchanon quoted the police as saying.
However, the police did not provide clear details and had no medical documents to prove that chemical substances found in Mr Vorayuth's body were the result of dental treatment, Mr Natchanon said, adding it was just a verbal explanation.
This issue is important and the Royal Thai Police is duty-bound to provide an explanation to clear suspicion, Mr Natchanon said.
Meanwhile, Sira Jenjaka, chairman of the House committee on legal affairs, justice and human rights, said on Thursday that police will consider bringing a new drugs-related charge against Mr Vorayuth.
Mr Sira, a Palang Pracharath Party MP for Bangkok, said police who handled the case told the committee on Wednesday that a medical report containing results of a test on Mr Vorayuth was in a investigation file that had been submitted to prosecutors.
The results show there were "substances found in the body of Mr Vorayuth".
But the officers could not explain to the committee why they did not bring this charge from the beginning, Mr Sira said.
Three activists claimed previously they had evidence to prove that Mr Vorayuth had illicit chemical substances, including cocaine, in his system on Sept 3, 2012, the day of the fatal accident.
They cited a 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.
Mr Sira said on Thursday that his committee on the affairs of courts of justice and a panel on police will meet on Aug 5 to discuss the case.
Among those who will testify before the committee will be national police chief Pol Gen Chakthip Chaijinda, Nate Naksuk, director-general of the Department of Appellate Litigation, and assistant police chief, Pol Lt Gen Permpoon Chidchob, who decided not to oppose the prosecutors' acquittal as well as two new witnesses in the case, Mr Sira said.
็็He said that Mr Vorayuth and his lawyer have been invited to testify before the panel. If they fail to show up, they will be summoned using a law on the summons power of House committees.
Meanwhile, Warawit Sukboon, secretary-general of the National Anti-Corruption Commission (NACC), said on Thursday that the anti-graft agency is ready to investigate the prosecutors who dropped all charges against Mr Vorayuth.
He was speaking after lawyer Ronnarong Kaewphet led law students from across the country to lodge a petition with the anti-graft agency asking it to look into whether prosecutors who acquitted Mr Vorayuth exercised their power honestly and in line with the law.