"I suspect Yaowapha amassed unusual wealth while in her elected office," Alongkorn said yesterday at a press conference.

He said he wanted the National Counter Corruption Commission (NCCC) to look into Yaowapha's involvement in the Chinnicha Ville housing estate.

The NCCC should start by examining Yaowapha's assets statement, which might have been doctored to conceal ill-gotten gains stashed away in nominees' accounts, he said.

Yaowapha's nominees include her three children - Yosanan, Chinnicha and Chayapha - and a close aide, Sunisa Pathompreuk nee Wejchai, he added.

The NCCC might proceed to examine the composition of equity stakes in the holding company of the housing estate, the Bt256-million transaction for the plot to be developed and the Bt1-billion deal to merge four companies before kicking off the project, he said.

In another development, an NCCC panel has summoned Sirote Swasdipanich, director-general of the Revenue Department, to explain why he neglected to collect capital-gains tax relating to a Shin Corp share transaction.

The panel, led by NCCC member Somlak Jadkrabuanpol, is tasked to investigate tax liabilities incurred by the transfer of Shin shares done outside the stock market.

Before summoning Sirote, graft busters found that a Bt738-million transaction involving 4.5 million Shin shares in 1997 had not paid any tax.

The transaction in question happened between Bhanapot Damapong, Thaksin's brother-in-law, and Duangta Wongpakdee, nominee of Thaksin's wife Khunying Pojaman Shinawatra.

Sirote has 15 days to decide whether to comply with the summons. Should he choose not to testify, the panel can still wrap up its report for the full NCCC to rule whether to charge him.