The Asset Examina-tion Committee (AEC), the government's graft-buster, is to file charges against former prime minister Thaksin Shinawatra's brother-in-law, wife and maid for allegedly colluding to avoid paying tax.

The move shows the military-backed government is achieving progress in prosecuting alleged corruption at the top of the former government.

Sak Korsaengreueng, a member of an AEC sub-panel, said that his panel will propose the AEC establish a committee to investigate Thaksin's brother-in-law Bhanapot Damapong, wife Pojaman and family maid Duangta Wongpakdi.

The committee will then file charges against the three and summon them for questioning before submitting the results of its investigation to the AEC.

Sak added the AEC would also investigate whether Pojaman's personal secretary Kanjana Honghern and her husband, who is the broker who facilitated the share deal that the tax evasion allegations relate to, were involved.

The AEC also plans to summon Revenue Department officials for questioning over the deal.

The allegations relate to Shin Corp shares that Bhanapot took ownership of in November 1997. On Monday, the AEC said he must pay Bt546.12 million in tax on the shares.

Bhanapot has claimed that the shares were not subject to tax because Pojaman had given them to him as a gift, an argument rejected by an AEC committee.

The AEC has ordered him to pay the tax bill within 30 days of receiving official notification from the committee.

Bhanapot received 4.5 million shares worth Bt738 million from Pojaman in November 1997.

The tax bill covers the original amount he was liable for plus interest.

Bhanapot has played a key role coordinating between state officials and Thaksin and Pojaman since they co-established Shin Corp almost 16 years ago.

Bhanapot's pleasant and low-profile personality compared to Thaksin's has led most state officials to admire him, enabling him to deal with them smoothly on Thaksin's behalf.

When Thaksin entered the politics, he entrusted the running of Shin to Bhanapot as one of his key people. Bhanapot was Shin chairman until the Shinawatra family disposed of its almost 50 per cent stake in the company to Singapore's Temasek Holdings in January.

"Bhanapot is the first person Thaksin and Pojaman think of when they need a helping hand to do important jobs," an industry source said.

If Bhanapot really does have to pay the back taxes and defend his reputation, Pojaman is expected to step in and help pay the money he owes.