Plus, an overwhelming number of former MCC members, now part of the CPI (Maoists) are actually from Bengal, say officials.

A day before the hostage crisis began, with the attack on the Lakhisarai police station, Chameli Das (40), a prominent woman Maoist leader from Bihar was arrested in the city. Chameli — who was in the city to meet her husband and get some medical care which was unavailable in Patna — was picked up from a slum in Keshab Chandra Sen Street by the Bihar Police and Kolkata Special Task Force (STF).

Wanted at least in six cases, she was an important catch, the police said. She had been allegedly involved in the blowing up of Abeli SDO office in Munger district of Bihar in 2008 and the murder of a policeman the same year.

In another instance, The STF of the Kolkata police arrested a senior Maoist leader, Musafir Sahani alias Anand Sahani alias Aloke alias Manik from a hotel in Central Kolkata this month. According to officers, Sahani has over 20 cases registered against him with the Bihar Police.

Active in north Bihar, he came to the city to meet a linkman, said a senior STF official.

Prior to these arrests, the Kolkata police intercepted a vehicle carrying about 5,000 rounds of ammunition meant for a key contact who supplied arms to the underground movements — including the Maoists in Lalgarh — the police said.

In October 2009, Chandra Bhusan Yadav, a hardcore Maoist was arrested from Hooghly by the CID and Jharkhand police. He had 16 criminal cases against him in Jharkhand and was active in Gumla, Latehar and Lohardaga districts of the state. He was an area commander of Koelshankar.

Reports by the state and Central security forces reveal that there are strong support bases in the city, particularly from a section of the intellectual community.

The Special Area Committee (SAC) of the CPI-Maoists for Bihar and Jharkhand are equivalent to the state committee of Maoists in Bengal. The SAC has always been ruled largely by the MCC faction. Six of the eight MCC members in the Maoist Central Committee are from Bengal, said a state government official specialising on Maoists.

“Most of the MCC members of the CC of Bihar and Jharkhand have their roots in Bengal, particularly in Kolkata,” he said. “Leaders like Kishenda — a CC member who reportedly operates in Pareshnath hills in Bihar-Jharkhand border. Apart from Kishenda, Jhantu Mukherjee, Kanchan, Manoj and Paresh — all CC members of the MCC faction mostly belonged to South and North 24 Parganas and Hooghly.”

It has also been mentioned in the intelligence reports that Kishenji visited the city and stayed on its outskirts for several months during 1995-2007.

At the time, he was busy preparing the intellectual support base of the city to begin the upsurge in Lalgarh.

Security surveillance has revealed that Maoist cadres and leaders often took shelter for medical care in the city. A Maoist linkman form Orissa got in touch with Sabyasachi Ponda, in charge of Orissa state committee of the Maoists, stayed in the city in 2008-09 using the name Rajshekhar.