Santhan, a convict in the Rajiv Gandhi assassination case who was later freed by the Supreme Court, died in Chennai on Wednesday following a cardiac arrest, a government official said.

Santhan alias T Suthendiraraja (55) is a Sri Lankan national and was one of the seven persons set free by the Supreme Court in 2022 after they served over 20 years of jail term in connection with the killing of the former prime minister near Chennai in 1991.

E Theranirajan, Dean of the Rajiv Gandhi Government General Hospital where Santhan was undergoing treatment for "liver failure", said he died at 7.50 am.

Santhan suffered a cardiac arrest around 4 am on Wednesday but was 'revived' following a CPR (Cardiopulmonary resuscitation) procedure and was given an oxygen supply and was on a ventilator, Theranirajan told reporters.

However, Santhan did not respond to treatment "and he died at 7.50 am today," he said.

"A post mortem will be conducted....legal arrangements are underway for the body to be sent to Sri Lanka," he added.

The deceased was admitted to the hospital in Chennai from a special camp in Tiruchirappalli, where he was lodged post his release, on January 27 for "liver failure", the dean said.