The National Anti-Corruption Commission (NACC) has found grounds supporting the allegation that former finance minister Thanong Bidaya broke the law in a deal to supply Rolls-Royce engines for Thai Airways International (THAI) three decades ago, according to Isranews.
Citing a NACC source, the news agency said the commission voted 6 to 2 to back the claim against Mr Thanong who was serving as THAI chairman and the airline's adviser on long-term investments when the scandal erupted.
The NACC also ruled a similar illegal act in the engine procurement was committed by Kaweepan Ruengpaka, THAI's former vice president for finances.
According to Isranews, the commission found both Mr Thanong and Mr Kaweepan had breached Sections 8 and 11 of the State Employees Offences Act.
Section 8 imposes hefty punishments against a state employee who engages in corruption in procurement projects. The offenders are liable for between five to 20 years in jail, a fine from 2,000 to 40,000 baht, or both.
Under Section 11, a state employee who commits dereliction of duty or acts in a corrupt manner can face one to 10 years in jail, a fine of between 2,000 to 20,000 baht, or both.
The NACC source said two NACC members felt Mr Thanong only violated Section 11 under which the statute of limitations in the case has already expired.
For the Rolls-Royce bribery scandal, the NACC has earlier decided to formally accuse 10 out of 26 individuals linked to the deal, but noted that none were politicians.
The probe was launched after Rolls-Royce admitted misconduct to the British Serious Fraud Office (SFO) in January 2017.
The bribes, reaching upwards of 1.25 billion baht, were reportedly paid to secure THAI's purchase of three lots of Rolls-Royce Trent 800 turbofan engines.
In statements given to the SFO, Rolls-Royce admitted to paying about 254 million baht to individuals to help it secure a deal with the Thai government to purchase Rolls-Royce Trent 800 engines for six Boeing 777 aircraft and Trent 500 engines for seven Airbus A340 aircraft.
According to a statement of facts prepared in a British court, the bribery took place during periods between 1991 and 2005 and involved payments totalling about US$36.3 million (1.28 billion baht) to "regional intermediaries".
Some of the money was for "agents of the state of Thailand and employees of Thai Airways", the document said.