Police said one Natarajan has been arrested and search is on for two others.
Pasupathi Pandiyan belonging to Devendrakula Vellalar community was murdered near here about two years ago.
Muthupandian, an accused in the case and out on bail was on his way to the court for the hearing when Natarajan, part of a group of supporters of Pasupathi Pandiyan, allegedly hurled the bombs at his jeep, damaging it. Muthupandian, however, jumped out and managed to escape, police said.