The Bentley driver involved in an expressway collision that left eight people injured on Sunday was found to have narcotic substances in his system, police said on Friday, citing the results of a blood test.
An initial test showed the substance could be methamphetamine, ketamine, diazepam or nordiazepam, and a further test is being done to determine exactly what it was, said Pol Lt Gen Jirasan Kaewsaeng-Ek, deputy commissioner of the Metropolitan Police Bureau (MPB).
Pending the outcome of the new tests, Suthat Siwapiromrat will be summoned to answer an additional charge of driving under the influence of narcotics and related charges, said Pol Lt Gen Jirasan.
On Sunday night, the Bentley driven by Mr Suthat rammed into the back of a brand-new Mitsubishi Pajero in the middle lane of the Chaloem Maha Nakhon expressway. The impact caused the Pajero to overturn and swerve into the right lane before it was hit again by an oncoming truck driven by volunteer firefighters on their way to a blaze.
The incident left six people in the Pajero — one of them a four-year-old child — injured, along with two firefighters in the other vehicle.
The Bentley driver initially tried to hail a taxi to leave the scene but was stopped by first responders, who said he appeared intoxicated. He declined to blow into a breathalyser at the scene, claiming the impact of an airbag after the crash had left him with chest pains.
He was subsequently taken to Police General Hospital where a blood test showed an alcohol level of 10.73 milligrammes, well below the legal limit of 50mg. Police say the blood test was conducted within an hour of the incident but other sources said the delay was four hours, so the alcohol content could have been higher when the crash occurred.
The police handling of the case has drawn fierce criticism and accusations that the driver was being favoured because of his wealth and connections. Mr Suthat, a director of several companies and a well-known political donor, is a brother of New Economics Party leader Manoon Siwapiromrat.
In another development, the Department of Special Investigation (DSI) plans to reopen an old tax evasion case in which the same Bentley had been among 1,020 cars seized for inspection. The cars had been imported from the UK and their values allegedly under-reported in order to reduce the amount of import tax payable.
The DSI is now looking into a possible link between the Bentley driver and the people named as suspects in the tax evasion case.