The tocsin signalling frenetic activity before the polls is months away still, but the high notes of bugles, signifying the start of the battle campaign, has started sounding loud and clear. Three central agencies—the Central Bureau of Investigation (CBI), the Enforcement Directorate (ED) and the National Investigation Agency (NIA) summoned, sought papers from and grilled a number of Trinamool Congress leaders since August 24, prompting the TMC to allege that the Centre was using the agencies for “political vendetta”.