Satnam Singh Mann (25) died on August 4 at the government mental hospital here where he was shifted after his arrest and remand on Wednesday last, officials said.
According to the hospital staff, there were signs of torture on Mann's body.
Meanwhile, Mann's relatives, who arrived here, alleged that he died due to torture by police and jail officials.
After postmortem, the body would be taken to his home town in Bihar for cremation, the officials said.
Mann, who had claimed that he was a student of Law, was found lying unconscious in his cell. He was rushed to Medical College Hospital where he was declared dead on arrival.
Mann was arrested and remanded on August 1 as he tried to barge onto the podium of spiritual leader Mata Amritanandamayi at her Amratapuri Ashram at Vallikkavu in Kollam district.
He was shifted to the mental hospital here on Thursday as he was allegedly in a mentally disturbed state.
Mann created a panic at the ashram by screaming and rushing to the podium of Amritanandamayi, popularly known as "Amma", while she was giving blessings to devotees. He was stopped by devotees and security guards and handed over to police.
Meanwhile, CPI-M in Kerala sought a judicial probe, saying a crime branch probe was inadequate.
