He had three bundles of cash totalling 3 million baht in front of him at the press conference where he made the announcement.
The police chief affirmed the arrest of the suspect was the result of the arduous work of the investigation team led by Pol Gen Chakthip Chaichinda, the deputy police chief who would succeed him on Oct 1.
Other members of the team included Special Branch police led by Pol Lt Gen Chaiwat Ketworachai, Central Investigation Bureau police led by Pol Lt Gen Thitirat Nonghanpithak and Metropolitan Police led by Pol Lt Gen Srivarah Rangsipramanakul.
Pol Lt Gen Prawut Thawornsiri, the police spokesman, said officials were in the process of seeking court approval for arrest warrants for more suspects, but declined to elaborate.
Police on Saturday arrested a foreign suspect who has yet to be properly identified but who was believed to have been involved in making and passing the improvised explosives to the bombers. They also seized bomb-making materials and forged Turkish passports.