
Police had sought the court’s approval to issue the arrest warrant for the suspect, whom they refer to as “Dragon”, but the court said additional evidence must be provided before it would do so.
Police had earlier obtained arrest warrants for two men seen in security footage just before the two bomb blasts on a walkway connecting Siam Paragon and the BTS Siam station.
The names of the men were not given. They were said to have arrived by taxi at Siam Paragon.
Bangkok police chief Lt-General Srivara Ransibrahmanakul said the suspects were facing a criminal investigation and an investigation held under martial law.
He said police believed there were more than two people involved and the investigation to track them all down was 70 per cent completed.
He said he hoped the arrests would be made soon because he feared for the safety of the public.
In relation to prosecuting the suspects, Srivara said police had to work with other state agencies, including in the gathering of evidence, before seeking arrest warrants.
Investigators believe the two explosions are linked to a deadly blast, which killed two men in Min Buri during the Bangkok Shutdown protests almost a year ago.