A 30-year-old undertrial prisoner, who was arrested in a rape case two months back, was found hanging in an under-construction building at the sub-jail in Ragadi in Jajpur district on Wednesday. The deceased was identified as Balaram Behera of Karada village under Panikoili police station. Jail authorities shifted him to the community health centre (CHC), Korei, where doctors declared him dead. Police sent the body to the district headquarters hospital in Jajpur for autopsy, sources said.