Officials said Mahesh Patil had served as RFO in Sandur taluk and has been accused of helping Associated Mining Company owned by former minister G Janardhana Reddy, who has already been arrested by CBI in connection with the case.
The official, who was arrested last night and remanded to judicial custody, also faced allegations of helping Reddy with fake permits to transport iron ore illegally.
CBI has already arrested Deputy Conservator of Forest Muthaiah and a retired official of the mines and geology department S Raju in connection with the case.
With Mahesh's arrest,the number of officials arrested has risen to three.