Led by Captain Teansiri Montaiwet of Royal Thai Navy 3, Thalang officials and local village chiefs saw how discarded tyres were being used to reclaim land and build up a property that would have a big price tag if sold as a resort.
Signs announcing that the area is being replanted with mangroves by volunteers had been removed, the investigating group discovered.
They also found telltale signs of ATVs being used around the coast and burned trees.
The disputed area is at Bang Sai beach, near Cape Yamu.
It's alleged that Burmese workers have been paid to uproot all the mangroves planted by volunteers.
As the first step in pursuing the culprits, claims to chanote land titles are to be investigated.
Three areas nearby claimed as shrimp farms were also checked. The shrimp farms appear to be growing in size. A rifle and drug-taking paraphernalia were found at one of the farms recently.