The police team had finalised its work and was waiting for the translation of some more English documents. The investigation should not take long to complete, Seripisut said.

"We will need to thoroughly check the dossier before forwarding the case to the Attorney-General's Office," he said.

Surin could not be reached for comment on the charge of acting as a nominee for Temasek. Kularb Kaew was set up days before Singapore's Temasek Holdings announced its purchase of Shin Corp on January 23, 2006 from the Shinawatra and Damapong families. The acquisition hinged on Kularb Kaew, which had teamed up with Temasek's Cypress Holdings to take over half of the Shin Corp shares that were bought through Cedar Holdings.

Appearing on Kularb Kaew's shareholder list were famous businessmen Pong Sarasin and Suphadej Poonpipat.

Following criticism that both of them acted on behalf of Temasek and could have breached the Foreign Business Act, Pong and Suphadej reduced their stakes after Surin stepped in. In March Surin spent over Bt2 billion to buy new shares of Kularb Kaew.

Surin, holding some 68 per cent of Kularb Kaew, has insisted that he acted on behalf of no one. He said he was financially capable of making the investment and his decision was based on the attractive business outlook of Shin Corp. If Surin is defined as a nominee for Temasek, it could threaten to unravel the Shin Corp deal.

The Nation