Pol Lt Col Khanawit Thanawuthipong, investigative inspector of the Metropolitan Police Division 2, said Mr Chaiwat was wanted under an arrest warrant for the alleged assault of Surasak Sowatanangkun, a 27-year-old pilot trainee.
Mr Surasak was driving on the elevated tollway above Vibhavadi Rangsit Road in Bangkok to Don Mueang airport to see his examination result.
PDRC guards were blocking the tollway in front of the Thai PBS television station. Mr Surasak got out of his BMW 525 car and removed the PDRC's traffic cones, intending to reach his destination. Then he was surrounded and assaulted by PDRC guards.
Pol Lt Col Khanawit said that Mr Chaiwat, a native of Nakhon Thai district in Phitsanulok province, was arrested on Rachaphruek Road in Bang Ramat sub-district, Taling Chan, and confessed to the offence.