Fakruddin alias 'police' Fakruddin, Bilal Malik (both of Madurai) and Panna Ismail of Melapalayam in Tirunelveli district are suspected to be involved in the murder of Ramesh, Salem Superintendent of Police R Shaktivel said.
Anybody knowing their whereabouts can inform police and they would be suitably rewarded, Shaktivel said.
Ramesh (52) was hacked to death while he was returning home after visiting the BJP office on Friday night in Salem that sparked an outrage in the party which gave a call for a state-wide bandh on July 22.
Some three to four persons had murdered him, Shaktivel said.
The BJP has demanded that the Tamil Nadu government order a judicial probe into the murder, which was condemned by the party's national leaders with Gujarat Chief Minister and party's election campaign chief Narendra Modi and Leader of Opposition in the Lok Sabha Sushma Swaraj demanding action against the guilty.
The Coimbatore serial blasts before an election meeting to be addressed by senior BJP leader L K Advani had left 58 people dead and over 200 others injured.