This April 4, 2013 photo shows Sudipta Sen (in striped shirt), chairman of Saradha Group, being led to a Kolkata court after his arrest. (TOI file photo by Sajal Mukherjee)

Mamata Banerjee looks at her painting, which she drew on the stage during the inaugural program of North Bengal festival at Siliguri's Kanchenjunga Stadium, on January 1, 2013. (TOI photo by Kaushik Roy)

Kunal Ghosh (in blue tee) is one of the key accused in the Saradha scam. (TOI file photo by Avik Purkait)

NEW DELHI: The CBI ’s probe into the Saradha scam has reached uncomfortably close to West Bengal chief minister Mamata Banerjee , with the agency securing details from the income tax department on purchase of one of her paintings by Sudipta Sen , promoter of the now-bust chit fund company, for Rs 1.8 crore.Sources in the agency, which also plans to call Mamata’s confidant and former Union minister Mukul Roy for questioning after Diwali, said the details from the I-T department suggested that the jailed chief of Saradha group may have paid a tad too generously for Mamata’s work of art.CBI’s interest in the transaction between Sen and Mamata as part of a widening investigation into the alleged ponzi scheme coincides with the thickening perception about Saradha’s linkages with Trinamool leaders.During the Lok Sabha poll campaign, Prime Minister Narendra Modi had alleged that one of Mamata’s paintings went for Rs 1.8 crore. Though Sen had then denied having bought any of Mamata’s paintings, the I-T returns filed by Trinamool Congress show that his group indeed acquired one, CBI sources said.Also, the amount mentioned in Trinamool’s I-T return as the expenditure on hiring the venue for an exhibition of Mamata’s paintings was “way too excessive”.Mukul Roy, who was seen as a virtual number two in Trinamool until last week when his responsibilities were divided among others, will be the sixth senior party leader to be questioned by CBI in the scandal. A senior officer told TOI, “Yes, we will question him after Diwali.”Kunal Ghosh, TMC’s suspended member of Parliament who was arrested by CBI in connection with the Saradha scam, had accused Roy and other party heavyweights — Subhendu Adhikari and Madan Mitra — of involvement in the scam. CBI has already questioned two party Rajya Sabha MPs, one Lok Sabha MP and a state minister among others in the scandal.Ghosh, who said he was being singled out, wrote a letter to CBI seeking action against Roy, quoting conversations he purportedly had with Sen when the two were lodged in Alipore jail. During the conversation Ghosh asked, “Nizam Palace e sei boithaker pordin katha moto Mukul Roy pathiyechhilen Rajat Majumdar ke? (Did Mukul Roy send Rajat Majumdar after that meeting at Nizam Palace?”Sen responded by saying, “Hyan, ekta bank draft enechhilo. Katha holo anek. (Yes, he had brought a bank draft. We had a long conversation).”According to the letter, Sen fled a few days after the meeting.Roy’s name has since been mentioned by several other persons arrested by the SIT probing the scam.Sen’s chauffeur Arvind Chauhan had also taken Roy’s name after his release from jail. Chauhan said Sen met Roy at Nizam Palace just before the former slipped out of Kolkata. Sen had escaped to Kashmir.Asif Khan, former convener of TMC’s Uttar Pradesh unit and a Kolkata-based businessman, had also named Roy among those who used Saradha money to acquire an Urdu paper.Recently, during a public rally in West Midnapore’s Keshpur, Roy had said that if it was proved that he or any of his party colleagues had taken money or any kind of favour from the Saradha group, then he was ready to leave the party.The agency has accelerated its probe in the Saradha scam as it plans to finalize its first chargesheet soon.