A bulldozer and a road paver were set on fire in Trang province early on Tuesday in what police suspect was related to a business conflict.
The Muang Trang district police station was alerted to the fire in Ban Khuan Lor village in Tambon Nong Trut at 1am.
When fire engines arrived the two vehicles were already engulfed and totally damaged.
Both vehicles belong to a construction firm that had won a contract to build a road there. The two vehicles were parked in front of the house of Nunian Damjutti, mayor of Tambon Na Bin Lar Administrative Organisation.
Witnesses told police that they saw several men arrive on a pickup truck and the fire then broke out while the pickup sped away.
Police suspected that business conflict was behind the arson.