The police said the inmate was found missing during routine checking on Tuesday morning.
According to a police officer, the NLFT cadre was sentenced to life imprisonment after he was found guilty in multiple cases, including for murder and kidnapping.
Police stations across the state have been alerted and an intensive search operation has been launched to locate the convict.
The Border Security Force (BSF) has also been put on high alert to prevent the convict from crossing over to neighbouring Bangladesh.
The same militant had escaped twice before — from the central jail in 2016 and from the Kanchanpur sub-jail in 2022. He was re-arrested in 2023 and since then he was lodged at the central jail.
Sepahijala Superintendent of Police, Bogati Jagadeeswar Reddy, visited the central jail in Bishalgarh to take stock of the situation after the jailbreak.
There are around 650 inmates in the central jail located around 30 km from here.
Based out of Bangladesh, NLFT is a banned militant outfit.
IANS