
AC (Land) Asma Akter said the perpetrators broke a window at the back of the building and hurled petrol bombs around 3am.
The fire engulfed a room on the ground, damaging computers and important land documents, she said.
Later firefighters and police managed to bring the blaze under control.
Meanwhile, around 4:30am, the attackers set fire to Magura Registry office.
Though no documents were burnt two rooms used by deed writers were gutted, reports UNB.
Officer-in-charge Md Ayub Ali of Magura Sadar Police Station said bottles containing petrol were recovered and a special drive is underway to identify the culprits.
A case has been filed in this regard, he added.