Graftbuster Vicha Mahakun has made recommendations for a revamp of the justice system after his review of the hit-and-run case involving Red Bull scion Vorayuth "Boss" Yoovidhya.
He said fine-tuning laws governing the police force and criminal procedures would ensure relevant agencies conform to the same standards.
The recommendations contained observations that police probes lack independence and are prone to graft, while evidence can be tampered with and facts can be distorted.
The recommendations were in his four-page report he produced after being assigned by Prime Minister Prayut Chan-o-cha to look into the 2012 hit-and-run case, in which criminal charges against the Red Bull scion were dropped after reaching their statutes of limitation.
Various law enforcement units responsible for the original probe were not in sync, while some laws had loopholes that allowed the investigation to proceed slowly, resulting in the indictment being delayed, the report said.
"Discrepancies exist that put the poor at a disadvantage in the justice system, which lends credence to the popular saying that 'jails are for the incarceration of the poor'," it added.
The laws also provide leeway for corruption by state officials while the criminal investigation process has failed to keep up with the times and social and economic conditions, the report noted.
Regarding Mr Vorayuth, Mr Vicha said the Department of Special Investigation (DSI) and the National Anti-Corruption Commission (NACC) have decided to investigate his case on two fronts: corruption and drugs.
The DSI and NACC would look to see if drugs were used when the 2012 incident happened and whether corruption was at play when Mr Vorayuth's multiple criminal charges were dropped over the past few years.
The agencies will concentrate on the two different issues in the case, the DSI said.
The department will focus its probe around Mr Vorayuth's alleged use of cocaine and reckless driving that caused the death of a police officer in Bangkok eight years ago.
The NACC, on the other hand, is interested in whether officials, especially police officers and prosecutors, played a role in the dropping of multiple charges against Mr Vorayuth.
Mr Vicha, who heads a state-appointed committee probing the alleged mishandling of the hit-and-run case, said the DSI and NACC's acceptance of the case shows the authorities are not "sitting on their hands", as alleged by critics.
