DSI to investigate documents seized from SAO linked to collapsed building

Most of these documents will be used in the investigation of the collapse of the new SAO building in Bangkok’s Chatuchak district following an earthquake.

The Department of Special Investigation (DSI) announced that it has finished cataloging 121 boxes of documents sized from the State Audit Office (SAO). Most of these documents will be used in the investigation of the collapse of the new SAO building in Bangkok’s Chatuchak district following an earthquake.

The under-construction 30-storey building on Kamphaeng Phet 2 Road collapsed on March 28 due to the impact of an 8.2-magnitude earthquake near Mandalay, Myanmar, trapping more than a hundred workers inside.



DSI spokesman Pol Maj Woranan Srilam confirmed on Friday that all boxes of documents have been opened and sorted. The documents have been categorized into three sections:


Documents related to joint ventures responsible for construction, procurement of materials, and construction operations.
Design modification documents.
SAO’s own documents summarizing the entire construction process, from design to material procurement and construction procedures.


Documents deemed irrelevant will be returned to their original owners, said Woranan.

He added that the next steps involve a detailed review of the seized documents. The DSI plans to summon document owners for clarification and may invite witnesses present during the incident for further questioning.

Woranan said the investigation remains focused on collaborating with the Department of Public Works and Town & Country Planning and the Bang Sue Police Station to collect all forms of evidence, including concrete and steel materials, to determine if the collapse resulted from substandard materials or construction errors.

The DSI has instructed the investigation team to avoid dismantling any elevator shafts, as these areas are critical for evidence collection due to their complexity, he said.

Regarding the questioning of engineers, Woranan said significant progress has been made. Ten engineers are scheduled for interviews on Friday, marking the final round of inquiries. For engineers whose signatures were allegedly forged, verification is expected to be completed within 30 days, he added.

In addition, the DSI’s Consumer Protection Case Division will consult with the Department of Industrial Works regarding the issue of hazardous red dust, found in the factory of a steel manufacturer, to ascertain whether it is linked to the steel materials used in the construction.

(2025/05/02-00:00)