Police stopped Chonsawas at a checkpoint on New Phetchaburi Road nine days ago after he was observed driving erratically. Two aides and three women, including two well-known models, were said to have accompanied him.

Chonsawas allegedly refused to submit to a breath test, and police said he then assaulted Sergeant Prarob Saengnil.

Colonel Chakkri Khamkong, deputy chief of Metropolitan Police Division 1, took a search warrant yesterday afternoon to the Vattana company compound, which includes a Pure petrol station, showroom and garage - which was where the alleged assault and detention of Sergeant Prarob occurred.

In a two-hour search, police examined five security cameras and looked for other evidence.

Chonsawas, who arrived an hour after the police, said he fully cooperated with the investigation.

Chakkri said officials wanted to check for more evidence - such as the nametag Prarob claimed to have lost at the scene. They also wanted to check if security camera footage had been edited.

Chakkri said police would issue an arrest warrant for one identified aide reportedly involved in the assault and warrants for the two models, who allegedly assaulted Napassanant Possawong, the daughter of a well-known gold shop owner, at a Thong Lor restaurant earlier the same night.

The models, sisters Anchalee and Yossawadee Hassadeewijit, will hear charges against them on Friday.

Chakkri said Chonsawas had promised to accompany his aide and the sisters when they present themselves to the police this week.