On a tip-off, Kavi Nagar police arrested Chunnu alias Pradeep, Rajvir and Vodesh from Chiranjeev Vihar colony yesterday, DSP Ran Vijay Singh said.
He said the trio had confessed to the crime, and that they had been hired by the brother-in-law of Prashant Kaushik, the nephew of the deceased ex-councillor.
Hari Mohan Kaushik was shot at indiscriminately by the three bike-borne men in front of his house in Shastri Nagar colony on October 16 injuring him severely.
Police recovered a country made pistol of .315 bore, two live cartridges, one knife and a bike used in the shootout and have sent the trio to jail.