The 23-year-old man was involved in cases of attack and assault and had been attending trial proceedings in a Kumbakonam court, they said.
He was staying in Kumbakonam but left for Ramanathapuram in 2016.
Police said he arrived here on August 28 and was staying at his relative's house.
Last night, five unidentified persons wearing helmets barged into the house and hacked him to death.