Isakki Muthu, arrested in connection with the July 11 murder of local AIADMK functionary Jeyapandian, was shifted here only a few days ago from Madurai prison on the orders of Madras High Court Bench to ensure protection to his life on a petition from him.
Police said Muthu, arrested on July 15, complained of stomach pain and diarrhoea last night. He was being taken to a hospital this morning when he suffered heart attack and died, they said.
In a complaint to the Chief Minister's cell, Muthu's wife Maheswari said her husband had no links with the murder of Jeyapandian. But the police officials took him by force and tortured him.
Her husband had said he was feeling insecure when she met him at the prison here, she said adding she suspected some conspiracy behind his death.
She demanded that postmortem of his body should be videographed and action be taken against those responsible for his death.