A prisoner, Nikhil Roy, allegedly killed another prisoner Upen Barman (72) inside a prisoners' cell at North Bengal Medical College and Hospital in Darjeeling district's Siliguri town on Tuesday afternoon.
Roy, a murder accused, a resident of Dhupguri in Jalpaiguri district, was admitted to the hospital recently, while Barman, who was an active member of the Greater Cooch Behar Democratic Party (GCPA), was arrested by police during a Rail Roko agitation recently and was admitted to the hospital on April 8 with a leg injury.
After they heard loud noise, police guards rushed to the prisoners' cell and found Barman in critical condition.
A heavy police force led with the Police Commissioner rushed the spot to take stock of the situation.
The Police Commissioner said police have started investigation into the incident.