Calcutta, Nov. 21: The CBI today arrested Srinjoy Bose, the Trinamul Rajya Sabha member and one of the famous five who figure in Mamata Banerjee’s original “chor”-coated clean chit, in the Saradha case.

The arrest of Bose, Trinamul’s second MP-in-custody after Kunal Ghosh, has emboldened the Opposition to demand that the chief minister be arrested and interrogated.

“Bose has been arrested for prima facie involvement in a case relating to Saradha Realty on charges of criminal conspiracy, misappropriation of funds and deriving undue financial benefits,” said a CBI official.

A purported letter by Sudipta Sen, the Saradha boss, to the CBI last year has specific references to Bose (known as Tumpai) and Pratidin, a Bengali newspaper of which the MP is the editor-in-chief.

“The most significant part of the letter was Sen’s claim that his deals with Pratidin would fetch him protection from both the state and central governments and an alleged assurance that they (Bose and Kunal Ghosh, the suspended Trinamul MP who had been arrested earlier) had a very close connection with the chief minister,” a CBI official said.

Citing such proximity and promising smooth passage, according to the letter, Srinjoy and Ghosh made monetary agreements with Sen.

According to the letter, Sen was supposed to pay Rs 60 lakh a month to Pratidin and appoint Ghosh as CEO of a channel at a salary of Rs 15 lakh a month. The letter claimed that organisations headed by Srinjoy took Rs 20 crore from Sen.

The letter portrays a classic case of political protection being sold for a price. “Pratidinhas also given me assurance that execution of this agreement… will protect my business from the government i.e. state government and also central government and I will be able to get a smooth passage and they assured me that they have very close connection with present CM of West Bengal i.e. Ms. Mamata Banerjee,” the letter says.

Bose ran for the Rajya Sabha on a Trinamul ticket after the term of his father, Swapan Sadhan (Tutu) Bose, was over. Other than the media venture, the Bose family has been engaged in cargo-handling in various ports in India and abroad. The younger Bose is also the assistant secretary of the Mohun Bagan club.

Bose, 38, kept a low profile in politics but was pitch-forked into eternal limelight when Mamata added his name to a cringe-inducing quote attributed to her soon after the Saradha scandal broke.

“Kunal chor? Madan chor? Tumpai chor? Mukul chor? Aami chor? Sabai chor? Baki ra shob sadhu (Is Kunal a thief? Is Madan a thief? Is Tumpai a thief? Is Mukul a thief? Am I a thief? Are all of us thieves? And the rest are saints)!” a Trinamul leader had quoted the chief minister as telling a party meeting on May 3, 2013. The chief minister has not distanced herself from the statement till now.

Today, arrested after six hours of questioning and asked whether he wanted to inform his party leaders, Srinjoy apparently said he had dissociated himself mentally from the party long ago.

The party, evidently, has not. Trinamul said today: “The CBI is a political tool used by the previous government to settle political scores. Now the BJP is doing an action replay. They cannot combat the Trinamul politically. They have tried and failed. So what do they do? Let loose a discredited CBI.”

The response is in sharp contrast with the fury and eventual denouncement that hit Ghosh when he sought a CBI probe and pointed fingers at Mamata,

But Opposition leader Surjya Kanta Mishra drew a parallel with Jayalalithaa, demanded Mamata’s arrest and said: “After Srinjoy Bose’s arrest, we demand that the CBI interrogate the chief minister.”

Insiders said that when Srinjoy was asked to clarify certain parts of the deal with Sen, he fumbled. The investigators allowed him to have short breaks in between to help him gather his thoughts. “But he repeatedly failed to clarify the discrepancies and we had to take him to custody,” said an officer.

Immediately thereafter, Bose was allowed to make calls to his family members and a few of his acquaintances. “He was also asked whether he wanted anything in particular. The MP asked for a cup of green tea,” said another source.