Chief minister Mamata Banerjee on Wednesday “challenged” the BJP to prove allegations that “chit fund walas had bought her paintings for crores” while declaring the party and its “rude” chief Amit Shah “unfit for politics and governance”.

“Modibabu, did Mamata take money from the sale of her paintings? Prove it. Prove she took a single paisa in her account. I challenge you,” the Trinamul chief said at a government event in Birbhum’s Rampurhat, a day after Shah made the allegations at a rally in East Midnapore’s Contai.

Declaring the “expiry date” of the Narendra Modi government had arrived, Mamata likened Shah’s speech to “the rudeness of the savages”. “(The speech was) not even bare minimum by way of courtesy. Unfit for politics, unfit for governance…. Our party has sent a notice of defamation (to Shah) and will file a defamation (suit) also.”

Shah’s allegations coincided with an acceleration in CBI investigations into deposit default scams in Bengal. “If I paint, it is theft. If I write, it is theft….A party of goons and cheats. Who are they to ask me these questions? What audacity!” she said, adding people know her well enough for her not to need character certificates from the BJP.

Trinamul sources said the central probe agencies were yet to target the Trinamul leadership since the release of party MPs Sudip Bandyopadhyay and Tapas Pal in deposit cases. However, since the recent arrests of two civil society members close to the ruling establishment, there are apprehensions of a crackdown ahead of the Lok Sabha polls.

“You can’t do anything on the soil of Bengal by trying to scare us with your CBI…The Rafale cat will be out, you will too. The demonetisation cat will be out, you will too. The GST cat will be out, you will too,” said Mamata.