Pol Lt Gen Prawut said anger among human trafficking gangs whose illegal businesses had been hindered by the government's crackdown was still the most likely motive for the bomb.
National police chief Somyot Poompunmuang is due to give a further update tomorrow on the shrine bombing case and the related explosion at the Sathon pier on Aug 18. More arrest warrants would be sought for other suspects this week.
Mr Karadag has been charged with premeditated murder.
“Today, police are confident Adem and Yusufu are the real attackers,” Pol Gen Somyot said yesterday. "Adem is the yellow-shirted man who planted the bomb. Yusufu is the one who exploded the bomb.