Police are expected to issue arrest warrants next week for three groups of people allegedly involved in the collapse of the State Audit Office's (SAO) under-construction building during the earthquake on March 28.
Pol Maj Gen Noppasin Poolsawat, deputy chief of the Metropolitan Police Bureau, said yesterday that investigators had so far questioned 193 witnesses.
They included SAO officials, relatives of the injured, the contracted designers of the building, the construction supervisors, and construction workers.
He said investigators have been gathering various kinds of evidence, including witness testimonies, circumstantial evidence, physical evidence, and documentation ranging from the drafting of the terms of reference (TOR), contracts for design, supervision, and construction, to material evidence such as steel and concrete fragments.
The investigation has focused on three groups -- the design team, which comprises directors and engineers associated with Forum Architect and Meinhardt (Thailand); the construction team, which comprises directors and engineers linked to ITD-CREC, a joint venture between SET-listed Italian-Thai Development and China Railway Number 10 (Thailand); and the construction supervision team, made up of directors and engineers associated with PKW, a joint venture between PN Synchronize, KP Consultants and Management, and W and Associates Consultants.
Pol Maj Gen Noppasin said the design blueprint for the 30-storey building had been sent to the Council of Engineers, the Engineering Institute of Thailand, and engineering experts at Chulalongkorn University to determine whether it complied with engineering and architectural standards, construction principles, and other relevant ministerial regulations. The results of this assessment are expected next week.
Investigators have so far gathered 315 pieces of material evidence from the site, including steel and concrete samples. Initial analysis of samples has been completed, but results are expected next week, he said.
Alterations were made to the elevator design, he added.