Mamata Banerjee's party's tussle with the BJP over the attack on its chief JP Nadda's convoy rolled on to Saturday with the Trinamool Congress accusing Union Home Minister Amit Shah of "indirectly trying to impose emergency in Bengal... by terrorising IAS and IPS officers of the state". In a letter to the Union Home Secretary Ajay Bhalla, who reports to Mr Shah, Trinamool MP Kalyan Banerjee has protested his ministry's letter dated Friday which asked the chief secretary of Bengal to release three Indian Police Service (IPS) officers for "central deputation".