Arunraj was discovered in a pool of blood during the early hours of Sunday.
A 28-year old policeman posted on duty at the memorial of late Chief Minister J Jayalalithaa allegedly committed suicide by shooting himself today, police said.
M Arunraj, a native of Madurai and attached to the armed reserve, allegedly took the extreme step early in the morning by shooting himself in his neck using his .303 service rifle, they said.
He died on the spot.
A senior police official said the cause of the incident was being probed into.