Serial rapist and murderer M Jayashankar committed suicide at the Parappana Agrahara Central Prisons in the early hours of Tuesday.
Police suspect that he slit his throat using a blade that he got during a haircut/shave within the jail premises.
The convict who was in isolation was kept in a separate cell and did not mingle with any other convict, the police said.
He slit his throat around 2.15 am, and was taken to the jail hospital. From there he was shifted to Victoria Hospital where he died around 5.15 am.
Parappana Agrahara police have registered a case of unnatural death under suspicious circumstances and are probing in to his death.
The police are also looking for his recent visitor records to ascertain what could have led him to take the extreme step.
Prison sources said he slit his throat using a piece of sharp-edged aluminium, a broken piece of an old eating plate, but a senior police officer confirmed it was a blade.
In 2013, he had scaled the walls of the Central Prisons using bedsheets and escaped. He sustained a leg fracture and was seeking asylum at a nearby slum from where he was arrested by the police.