Vijay Singh had fired at assistant town planner Shail Bala Sharma, who was leading a SC mandated demolition drive against illegal structures, and fled.
Army has also been alerted and there is a heightened vigil, police said.
The Union home ministry, from its North Block office atop the Raisina Hill in New Delhi, kept a 'constant and engaging' vigil across the country with central paramilitary forces, intelligence agencies and state police forces in toe.
According to reports from the states, several congregation participants are yet to show up before authorities.
In the wake of the terrorist attack on the Pathankot Air Force Base, security was on Saturday stepped up in the national capital and several states. Security has been beefed up at the airport, railway stations, bus stands and other vital installations.
T20 World Cup-winning cricketer Joginder Sharma, Commonwealth Games gold medal-winning boxer Akhil Kumar and Asian Games champion kabaddi player Ajay Thakur are all full-time police officers, jobs which they got thanks to their sporting accomplishments.
In the wake of the National Investigation Agency issuing a fresh alert to the Himachal Pradesh Police about a possible strike on the Buddhist people and their places of worship in the state, the investigation agency has been probing a couple of youth from Assam in connection with the Bodh Gaya attack.