Thanyaburi Court in Pathum Thani province on Wednesday approved warrants for the arrest of five construction bosses allegedly at fault in the fatal collapse of a condominium building on Monday evening.
The five were identified as sub-contractor Diaw Prabjone, 43, Mrs Pensri Kitipaisalnont, 48, who sought construction permission, engineer Saksit Inthong, 43, who designed the building, Jira Khanman, the engineer who supervised the construction, and Chanaichon Kerdthes, the managing director of the construction company Plook Plang.
Pathum Thani police chief Pol Maj Gen Samit Mukdasanit said they were charged with recklessness causing death.
Later it was reported that Mr Diaw had been arrested and the other suspects planned to surrender.
Police questioned 20 witnesses, most of them construction workers who survived the collapse of the incomplete six-storey structure.
Police said they believed there were more people than the 33 construction workers recorded as working on the site at the time, so there could be more victims.
The building collapse happened near the end of the afternoon work shift, so relatives of the workers might also have been at the site, Pol Maj Gen Samit said.
Pathum Thani governor Pongsathorn Sajjacholaphan said sniffer dogs were deployed at the site of the collapsed U-Place condominium to locate any victims still under the debris.
If there were no vital signs of life, workers would use heavy machinery to quickly break into the rubble.
Jirasuk Sugandhajati, permanent secretary for labour, said the official death toll remained at three. They are Chettha Kumphuchart, a seven-month pregnant woman identified only as Uan and her four-year-old son.
There were 25 injured and 20 of them were treated at hospitals. On Wednesday six of them remained at four hospitals. Authorities believed four more people were still trapped in the debris.
Mr Jirasuk said those victims who were Social Security members would receive compensation right away. For those were not covered, the Social Security Office would order employers to pay legal compensation.
Thienrat Nawamawat, labour chief of Pathum Thani, said Cambodian authorities reported that three Cambodian workers were missing at the U-Place construction site.