Case investigator Pol Lt-Colonel Thitichat Phanniam said police had not obtained eyewitness accounts apart from the police's own statement on Thursday quoting a vendor who said she had seen Kiartipong Meksawat arrive at the market with two unidentified men.

The officer quoted some witnesses as saying the two men had "only watched" the incident from near a police box when the bloody shoot-out started at 4am on Wednesday.

"Police have not yet found any evidence linking them with the shooting," he added.

Klong Luang station chief Pol Colonel Surasak Khunnarong said Kiartipong had legally bought a motorcycle through a website and met the seller at Thai Market to pay the money at 5pm.

He later parked it in a restricted area, and the Thai Market's security guards then impounded it.

Market director Manas Wilairat gave a conflicting account, saying that Kiartipong had come to the market with the two men at 9pm on Tuesday. He said Kiartipong had become angry after he was searched by police on refusing to show his ID card and ownership documents for the motorcycle.

Many vendors said they had seen Kiartipong sitting and crying on his own in the market at around midnight. He then left and returned at around 3am. Some of them said they believed Kiartipong had been verbally abused or assaulted by security guards.

A vendor said Thai Market's guards had long been known for their aggressive manner and frequent use of force against vendors, taxi-drivers entering the compound with passes and even buyers who parked their cars in restricted areas. The vendor said she had witnessed the guards' verbal abuse, intimidation and assault throughout the many years she had sold her wares at the market.

Meanwhile, Culture Minister Khunying Khaisri Sriaroon said she would use the shoot-out as a catalyst to urge a media-watch committee under her supervision to raise awareness of children being exposed to violence-prone media content and computer games.

Along with files containing information on firearms and explosives downloaded from the Internet found in Kiartipong's computer in his apartment, police found a large number of computer games involving shooting and violent martial  arts.