A mass shooting incident occurred at a famous fresh food market in the Thai capital on July 28.
Police said four security guards were killed and another was injured in the gunfighting.
"The police are investigating the motive. So far, this is a mass shooting case," AFP quoted Worapat Sukthai, Deputy Chief of Police of Bang Sue District, Bangkok, where the incident occurred.
Thai police officials added that the shooter had committed suicide.
The latest shooting in Thailand occurred at Or Tor Kor market, near a police station in Bang Sue district.
The suspect opened fire at many people in Bangkok's crowded market.
After the incident, the shopper was asked to urgently evacuate the area.
Some local media have published photos of the suspect, showing him wearing thorny wereo pants, black T-shirts and a white boy's tongue hat, carrying a backpack in front of his chest.
