Police have confirmed that 12 million baht in cash found in a plastic box near a condominium's rubbish area in Nonthaburi belongs to Taweewat Sengkaew, a lawyer and adviser to the National Broadcasting and Telecommunications Commission (NBTC).
However, investigators say his income records do not match his being in possession of such a large sum.
Mr Taweewat came forward to claim the money on Friday, after the box was discovered earlier that week.
Pol Lt Gen Surapol Prembut, commissioner of Provincial Police Region 1, said on Tuesday that Mr Taweewat has been questioned as a witness and provided useful information.
Video footage from the condominium showed that the cash box was previously inside his unit, which had suffered from water leaks, matching his testimony.
Police believe the money is indeed his, but are investigating further to confirm whose bank account it was withdrawn from, who made the withdrawals, and how the cash came to be stored in the condo.
According to Pol Lt Gen Surapol, the withdrawals reportedly occurred in May 2020, over several transactions.
Mr Taweewat claimed that political reasons were partly behind his decision to withdraw the cash, but the details remain confidential.
Still, investigators say the financial documents he provided do not align with having 12 million baht in legitimate income.
Pol Lt Gen Surapol noted it was unusual to store such a large amount of cash in a room.
Police plan to summon Mr Taweewat's wife for further questioning and continue examining all the related evidence.
Meanwhile, Pol Maj Gen Charoonkiat Pankaew, deputy commissioner of the Central Investigation Bureau (CIB), said that multiple anti-corruption agencies, including the CIB, the Office of the National Anti-Corruption Commission (NACC) and the Office of Public Sector Anti-Corruption Commission (PACC), will meet with police to map out the investigation and trace the source of the 12 million baht.
Authorities aim to determine whether the funds came from legal work, as Mr Taweewat claims, or from illegitimate sources.
Pol Maj Gen Jaroonkiat also questioned why the money was not stored in a bank or safe, calling the explanation unreasonable. He urged the public to remain patient, promising a clear outcome as the investigation proceeds.