Tonton Mishra alias 'Pandit-ji', who was brought to the court for production in a case of drug peddling, broke open a wall of the toilet using a crowbar and escaped.
Mishra's five associates too were brought from Burdwan Central Correctional Home from production. They were quarrelling inside the lock up in a loud voice to drown out the sound of breaking the wall, police said.
The crowbar used for the job was found inside the toilet but it was not immediately known how it reached there.
Police have started a manhunt for Mishra.
Hailing from Jamui district of Bihar, Mishra had been into drug peddling, supari killing and arms dealing in Bihar and Jharkhand.
Three years ago, he had escaped from a court lock up in Bihar and was staying in Kulti area of Burdwan. He was arrested by Burdwan police for drug peddling on April 4.