Amid the unprecedented showdown between the CBI and the Kolkata Police, the ruling Trinamool Congress Sunday wondered whether the BJP was attempting a constitutional coup in the state. A team of CBI officers was stopped from entering the residence of Kolkata Police chief Rajeev Kumar, when they had gone to question him in connection with chit fund scam cases, officials said. "BJP planning a constitutional coup? 40 CBI officials surround Kolkata Police Commissioner's home. Destruction of institutions goes on unabated. Our demand in #Parliament on Mon. Modi has to go. We are reaching out and sharing this with all Oppn parties who want to #SaveDemocracy," TMC national spokesperson Derek O' Brien tweeted. Throwing her weight behind the city police chief, West Bengal Chief Minister Mamata Banerjee rushed to his Loudon Street residence in central Kolkata. Reacting to the face-off, BJP national general secretary Kailash Vijayvergiya said the CBI is a noted organisation and any efforts to stop its activity should be condemned. Some CBI officers were forcefully taken to a police station from outside police commissioner's residence.