Forest Ranger Sidheshwar Singh was shot dead in the forest dak bungalow on March 13. Singh was living alone there.
"We have arrested Chetan Lakra and Manoj Bhuiyan, who was the driver of the slain ranger," said Sub-Divisional Police Officer (Chakradharpur), Ajay Kerketta.
He said police are looking for four more persons.
Singh was killed to loot Rs 10 lakh he had withdrawn from the bank and kept in the dak bungalow.
Kerketta said Bhuiyan, the driver, was aware of the money kept by Singh in the Dak Bungalow and informed his accomplices.