The Trinamool Congress hit out at the Centre after CBI summons Abhishek Banerjee wife in coal scam. TMC said that the investigating agencies have become the office of the BJP. Meanwhile, the CBI has been investigating the coal smuggling case since last year. The CBI suspected Abhishek Banerjee's wife due to some transactions by Anup Lala, the kingpin of coal smuggling. Watch video.