The raid was conducted jointly by prison officials and sleuths from the detective department of the Kolkata police.

The jail houses dreaded criminals like Aftab Ansari, the alleged mastermind of the attack on American Centre.

Interestingly, one of the cell phones started ringing during the raid despite jammers in place. State home secretary Ardhendu Sen said: “The raid was part of our drive in the run-up to Republic Day. Such raids will continue.”

“We are investigating as to how so many cellphones and a DVD player were recovered from the premises. The security arrangements are being thoroughly checked to develop a foolproof system,” said Additional Director-General (jails) B D Sharma.

The state Government had installed six sophisticated jammers in Alipore Central Jail on March 31, 2006. The jammers were installed by Webel Electronics Communication System at a cost of around Rs 20 lakh each.

However, according to jail sources, the raid exposed that vast areas of the jail premises remained out of coverage of jammers. “The six jammers were placed atop only a few cells. Vast areas in the jail were not covered by it. Only cell numbers 1, 2, 13, and 14 are covered by the jammers. Only one criminal is lodged in each of these cells. The hundreds of other undertrials and convicts who are in the wards are free to use cellphones since those areas are not covered. There is a gaping hole in security,” said a senior officer who took part in the surprise raid.

The raid went on for three hours during which the second floor of ward number 9, the ground and first floor of ward number 7 and the ground floor of ward number 8 were searched. All these wards house around 400-500 undertrials. Senior officials themselves rummaged through baggage of the inmates and even frisked them.

“During the search, six cellphones were found and three of them had SIM cards,” said Sharma. One of the cellphones was found while frisking an inmate, Zakir Sheikh, who is an accused in the infamous Basanti murder case. Later, at the ground floor of ward number 8, a DVD player was found wrapped in a blanket. A number of pornographic DVDs were also seized.

“The cellphone seized from Zakir was live and rang five times after we seized it. The phone was in silent mode. We are verifying the incoming and outgoing calls. The cellphones were used by these criminals for running extortion rings from inside the jail,” said an officer of the detective department.