The prisoner, Wahid Noor Khan, was being escorted to Central Jail Srinagar, police sources said. He died due to some explosion inside the police vehicle, they said.
Mr Khan was arrested in connection with a militancy-related case of 2010 and was scheduled to appear before a Sessions court in Sopore.
The sources said that five policemen, who were accompanying the detenu, were injured in the blast and admitted to SKIMS hospital in Srinagar.
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