Miscreants have set the Radhanagar union land office on fire in Chhagalnaiya upazila of Feni.
Chhagalnaiya police OC Rashedul Islam said the arson took place around 4am on Thursday.
Furniture and other important documents were gutted in the fire, he said.
The police also detained Radhanagar UP Chairman Rabiul Haq Chowdhury in connection with the incident.
The OC added: “Rabiul Haq is a BNP leader of the area. He was held in suspicion of the arson.”
On being informed, police officers and firefighters went to the spot and managed to douse the blaze.