The operation, led by Prachin Buri Police deputy superintendent Pol Lt Col Prasit Hakao, followed reports from local people of suspicious wood transportation and processing in the area.
Songkran admitted that the warehouse was his, but all valuable timber in the warehouse such as teak belonged to his sister Hatairat Thahin and brother-in-law Lai Seubsaeng, who bought it from the local people to build a house.
The estimated value of the timber was up to Bt5 million but the price could be double if the wood was processed.
Officers inspected the documents for the timber and found all were signed by Lai, who is the local forestry officer.
As Lai and Hatairat could not positively identify the seller of the wood, it was confiscated for further investigations.
Prasit said that if the wood was found to be illegal, Songkran might also face a charge of providing a place to store it.