Pol Lt-Colonel Prawut Wongsinil, chief of the DSI's consumer and environmental protection division, said department officials were dispatched yesterday to investigate.
For the Sirinat case, the DSI will inspect an aerial map of the 379 plots in question, covering 2,700 rai (432 hectares), he said.
Most of the plots reportedly had fake Sor Khor 1 land-possession certificates that provided wrong coordinates and plot territory, he said, adding that if title deeds for a plot were obtained, they could be sold for Bt30 million per rai.