Three devotees were killed and several others injured in the stampede near Gundicha temple on June 29 prompting Chief Minister Mohan Charan Majhi to order the administrative probe.
The defamation case has been filed against Divya and T V Prasanthan, an applicant for a petrol pump licence who had levelled bribery allegations against Naveen.
According to the collector’s statement, Naveen Babu admitted he had “committed a mistake” during a brief conversation after the farewell meeting on October 14.