"Many cases are making good progress and are closing in on the culprits," AEC spokesman Sak Korsaengruang said.

The AEC convened a full session to hear the latest reports from its 12 panels tasked to uncover evidence of irregularities by the former PM and his cohorts.

All ongoing investigations were still at the fact-finding stage and some of them could progress to a full-fledged hearing on graft and criminal violations by the end of this month, Sak said. At the hearing stage, the defence would be permitted to present evidence and rebuttals before moving on to the indictment, he said.

One panel investigating Bt9.9 billion in loans by state-controlled Krung Thai Bank and a real estate borrower seen as close to ousted leaders is expected to wrap up its work later this month, before recommending more proceedings.

Another panel will next week hear testimony from an executive of Exim Bank. The hearing will focus on a Bt4.4-billion loan extended to Burma at the urging of the deposed government.

A panel looking into the rubber sapling scandal will convene a hearing of witnesses on Monday.

The panel in charge of the CTX luggage scanners inquiry is tipped to enlarge its probe to cover the installation of conveyor belts in addition to the bomb scanners.

Another panel asked for tax audits relating to Shin stock transactions between Ample Rich Investment and two of Thaksin's children. It is waiting for a Revenue Department report on capital gains taxes owed to the government.

Tax lawyers for Panthongtae and Pinthongta Shinawatra have defended their share deals as qualifying for exemption.

After reviewing the 12 panels' reports, the AEC decided to form a new panel to investigate suspected foul play in the Thaksin regime's decision to allow mobile phone operators to deduct excise charges from their concession fees.