Serving life sentence, Jai Pal (66), a resident of Sonepat, had complained of severe chest pain last evening, jail authorities said.
The jail doctor examined him and gave some medicine, they said adding, this morning Pal was taken to civil hospital, where he was declared brought dead.
The body was handed over to his son Devender after the post mortem, DSP (Jail) Vishal Chibbe said.
