West Bengal Chief Minister Mamata Banerjee on Wednesday lashed out at the central government after an income tax raid at the house of the Tamil Nadu Chief Secretary.Banerjee dubbed the move "vindictive, unethical and technically improper action"."Earlier, the Principal Secretary of Arvind Kejriwal was raided and harassed. Now I read the Chief Secretary of Tamil Nadu has also been raided. Why this vindictive, unethical, technically improper action? Is it only to disturb the federal structure," the Trinamool Congress supremo asked on Twitter.Banerjee demanded to know why raids were not carried out on properties associated with Bharatiya Janata Party President Amit Shah and others."Why don't they raid Amit Shah and others who are collecting money? While corruption needs to be condemned strongly, the raid on Chief Secretary by central agencies devalues the institution of head of the civil service," she said.She said the Tamil Nadu leadership should have been taken into confidence prior to the raid."The proper procedure should have been (followed) to take the state leadership into confidence and removing him from the post prior to any pre-emptive action based on information," she added.