A former senior prosecutor for the Office of the Attorney-General (OAG) has filed a lawsuit against a former forensic officer who changed the recorded speed of the hit-and-run case of Red Bull scion Vorayuth "Boss" Yoovidhya in 2012.

Chainarong Saengthong-aram and his lawyer on Tuesday filed a lawsuit against Pol Col Thanasit Taengchan, a former officer from the Office of Police Forensic Science who inspected the hit-and-run scene in 2012 and later changed his statement to lower the car speed of Mr Vorayuth's Ferrari from 177kph to 79kph.

The lawyer claimed that Pol Col Thanasit wrongly identified Mr Chainarong as part of a group of people who forged documents, fabricated the evidence and edited the audio record. This led a panel that looked into irregularities surrounding this notorious hit-and-run case to believe that Mr Chainarong took part in tampering with the evidence.

Mr Chainarong was sacked in December last year.

When asked why Mr Chainarong filed the charge on Tuesday, the lawyer said it took time for the team to gather all the evidence.

Mr Vorayuth has been on the run since his Ferrari fatally hit a Thong Lor police officer on Sept 3, 2012.

Several charges against him were dropped, including a speeding charge, after its one-year statute of limitations expired in 2013, followed by another charge of failing to help a crash victim, which expired in 2017.

The only remaining charge against him is reckless driving causing death, which carries a penalty of up to 10 years in jail and has a 15-year statute of limitations, which will expire in 2027.