Head Constable S P Singh, who was on leave from duty, was found dead in his room at around 3:00 AM in the district, officials said.
Singh, of the 12th Central Reserve Police Force battalion, hailed from Kawalpitti village in the Thoothukudi district.
"A team of local police and senior CRPF officials soon reached the spot.
"A Court of Inquiry has been ordered by the paramilitary. He was on leave for the last few days," they said.