The December 26 clash in front of the ThaiJapanese Stadium, which was being used for candidacy registration, claimed two lives and injured hundreds others.
The “men in black” referred to by the police chief were spotted on the roof of the Labour Ministry's building near the stadium on Vibhavadi Rangsit road in Din Daeng district. Others in antiriot uniforms were seen smashing the vehicle of a volunteer nurse parked near the stadium.
He vowed to investigate and bring them to justice.
Adul’s comment came as he led senior police officers to deliver best wishes and receive New Year blessings from the president of the Privy Council Gen Prem Tinsulanonda this morning.
Earlier police spokesman Pol Maj Gen PIya Uthayo claimed the men in black were actually protesters in police uniforms, who had broken into police cars and stolen antiriot gear.