"Three cases have been lodged against unidentified persons," IG (Law and Order) Bhagwan Swaroop told reporters.
He said 21 vehicles, including two buses, seven four- wheelers and 20 two-wheelers were torched, and 57 others were vandalised by the protesters.
"No arrest has been made so far," he said, adding efforts were being made to identify the trouble-markers by reviewing the video-footage and photographs of the incident.
The protest by lawyers had erupted after the body of 40-year-old advocate Sharavan Kumar Verma bearing injury marks was found in a drain close to the place where he stayed in Ganeshganj locality, police said.