Jakarta, Aug. 10 -- Indonesia's Forestry Ministry has arrested three suspects for illegally trading and farming land inside a protected forest in South Sulawesi, uncovering an informal land-rights sales scheme, officials confirmed Monday.

"Practices like this must be stopped immediately. State forest areas cannot be bought, sold, or transferred without valid legal permits," said Ali Bahri, head of the ministry's Sulawesi Forestry Law Enforcement Agency.

The suspects, identified by their initials AR, AI, and AW, were caught red-handed on August 3 after illegally clearing 1.5 hectares of protected land in East Luwu Regency to plant roughly 1,500 pepper trees.

Investigators found the suspects had acquired the plot through an informal land...