Kolkata, May 20 : Security in and around the Central Bureau of Investigation (CBI) office here was tightened on Saturday over the arrival of Trinamool Congress national general secretary Abhishek Banerjee for interrogation in the school recruitment case in West Bengal. The Central Reserve Police Force (CRPF), which is in charge of the security of the inner circle of Nizam Palace complex, has increased the strength of its personnel on duty. The external circle of the Nizam Palace complex and the road connecting to it are under the control of the personnel of Kolkata police since this morning. While guardrails have been placed at several places, both uniformed and plain dressed personnel of Kolkata police are present in every nook and cranny of the roads adjacent to Nizam Palace. Two officers in the rank of deputy commissioner of police, assisted by four assistant commissioners, four inspectors and 16 sub-inspectors are in charge of the security arrangements outside Nizam Palace. To recall, in 2021 when two West Bengal ministers, one Trinamool Congress legislator and one former mayor of Kolkata Municipal Corporation were arrested by CBI and brought to Nizam Palace, thousands of ruling party activists assembled in front of the CBI offices and staged protest demonstrations. Incidents of brick-batting were also reported then. Probably, the massive police arrangement since this morning was keeping that in mind. /IANS