A CBI team had shown up at Kolkata Police Commissioner Rajeev Kumar's home on Sunday evening. The CBI has accused Kumar of hindering investigations into the Saradha and Rose Valley ponzi schemes.
The TMC's Derek O'Brien said 40 officials of the CBI had shown up, and that they did not "even have a search warrant".
Praveen Tripathi, Joint Commissioner Crime, Kolkata Police: A team of CBI officers came without any papers for what they called a 'secret operation'. When asked what the operation was about, they could not give a satisfactory response. pic.twitter.com/CyS83Z1aKC
Mamata said the CBI's turning up announced amounted to the "destruction of the federal structure".
"I am going to stage a dharna to save the federal structure. From today I'm going to sit near the Metro Channel. Tomorrow proceedings in state assembly will take place where I will hold a meeting. This dharna means satyagraha," she said.
Kolkata police chief Rajeev Kumar sat with Mamata on her protest.
West Bengal CM Mamata Banerjee: I am going to stage a dharna to save the federal structure. From today I'm going to sit near the Metro Channel. Tomorrow proceedings in state assembly will take place where I will hold a meeting. This dharna means satyagraha. pic.twitter.com/vL6My4UA6G
"... constitution is in danger, institutions are in danger and the country is in danger. Mamata has fought many battles before and another one starts tonight at 9 pm," O'Brien said.
He added that the "TMC has spoken to all like-minded parties and given them an update on what happened today in Kolkata. It has happened to Akhilesh Yadav, Mayawati, Congress, TDP, AAP and all the parties."
Derek O'Brien, TMC: Amit Shah and Narendra Modi cannot fight TMC. They are resorting to political vendetta after what they saw in United India rally. BJP knows TMC slogan has arrived - '2019-BJP Finish' pic.twitter.com/WZYYRUaEsc
The BJP meanwhile said Mamata was behaving "like a dictator... to protect the corrupt in her state".
"Incident taking place in Kolkata are unfortunate," said BJP spokesperson GVL Narasimha Rao. "Mamata Banerjee wants to protect the corrupt in her state, like a dictator. She is obstructing investigation of CBI which was there as per SC order. She is shredding apart the constitution. We condemn this."
GVL Narasimha Rao, BJP: Incident taking place in Kolkata are unfortunate. Mamata Banerjee wants to protect the corrupt in her state, like a dictator. She is obstructing investigation of CBI which was there as per SC order. She is shredding apart the constitution. We condemn this. pic.twitter.com/ayoxDVAsUb
Rao added that "CBI is working as per directions of SC, no state government has the power to obstruct or detain them. It's unconstitutional and undemocratic... We hope SC gives a direction to WB government, keeping this incident in view otherwise no agency will be able to work in this country."
The events of Sunday evening could very quickly snowball into a constitutional crisis.
Five men of the CBI team were detained, but later released.
And even as the CBI team arrived on Kumar's doorstep, personnel of the Kolkata Police stationed themselves outside the regional CBI office.
Interim CBI Director M Nageshwar Rao meanwhile told ANI on Sunday evening that "we are investigating these chit fund cases as per the directions of the SC. An SIT has been constituted by the WB government prior to SC's direction under the chairmanship of Rajeev Kumar, who is currently the Kolkata police commissioner."
He added that "they have taken charge of all the evidence, seized all the documents. They have not been cooperating with us in handing over all the documents and a lot of evidence has been destroyed or caused to disappear. There is evidence against him (Rajeev Kumar), he has been instrumental in causing destruction of this evidence and obstructing justice."
By about 10.30 pm Sunday night, reports began to filter in of TMC workers staging protests in the state.
West Bengal: Visuals of TMC workers burning an effigy of Prime Minister Narendra Modi in Asansol over the ongoing CBI issue. pic.twitter.com/DiYkBzaK2g
A number of opposition leaders meanwhile, including Rahul Gandhi, Omar Abdullah, Akhilesh Yadav, Tejashwi Yadav, Chandrababu Naidu, Mayawati, Sharad Pawar, and Arvind Kejriwal, spoke to Mamata Banerjee over the phone and expressed their solidarity.
The CBI had on Sunday evening shown up at the Kolkata Police chief's home, accusing him of hindering the investigations into the Saradha and Rose Valley ponzi schemes. Mamata said their turning up unannounced amounted to the 'destruction of the federal structure'.