Prime Minister Paetongtarn Shinawatra will expedite the issuing of arrest warrants for those involved in the collapse of the new State Audit Office (SAO) building once sufficient evidence is found.
Ms Paetongtarn on Friday convened a meeting to receive updates on the investigation with national police chief Pol Gen Kittharath Punpetch and Department of Special Investigation (DSI) director-general Pol Maj Yutthana Praedam among those in attendance.
Following the meeting, the prime minister said the Comptroller General's Department (CGD) would be enlisted to inspect construction material standards, as it has the authority to cancel contracts.
Ms Paetongtarn said the DSI is investigating possible violations involving substandard steel, poor concrete quality and the lack of steel reinforcement in the lift shaft.
Additional concerns include foreign shareholders and bid collusion.
She asked the media to help communicate to the public what the issues are and that the government will not let the matter drop.
Regarding legal proceedings, she confirmed that arrest warrants will be issued as soon as authorities have sufficient evidence.
"It won't be long until arrest warrants are issued," she said.
Ms Paetongtarn also said that some state agencies, including the SAO itself, are yet to provide requested documents, adding that any agency failing to cooperate would naturally draw public suspicion.
She said she has also pressed the police to find those responsible: "It's impossible that no one is at fault.
"We already know that there are clearly certain areas where things went wrong, unlike in other buildings. It's obvious," said the prime minister.
Pol Gen Somprasong Yentuam, assistant national police chief and head of the Metropolitan Police Bureau's Investigation Division, said arrest warrants might be issued within seven days, but more evidence is still required.
Meanwhile, the DSI on Friday searched the offices of companies linked to the building, including China Railway No.10 (Thailand).
Evidence seized included a dozen boxes of daily construction reports and a list of 51 supervising engineers.
In another development, Pimol Yingcharoen, an 85-year-old engineer allegedly listed as the original designer of the building, informed authorities he was ill and could not meet investigative officers. He promised he would report to the DSI next week after recovering from his illness.
As of Friday, the collapse had claimed 44 lives, injured nine and left 50 occupants still unaccounted for as search efforts continue.