"There is no serious case, nothing," said Mamata Banerjee

Highlights Mamata Banerjee came out in support of businessman Robert Vadra

"There is no serious case, nothing," Ms Banerjee said

"They (centre) are doing it deliberately ahead of the polls," she added

Bengal Chief Minister Mamata Banerjee today stood by her new resolution of a closer cooperation with the Congress, which is facing BJP attack after party chief Rahul Gandhi's brother-in-law Robert Vadra was questioned by the authorities in a money laundering case.

Asked about the questioning, Ms Banerjee brushed it off. "There is no serious case, nothing, just sending the notice casually to everybody. So we stand together, we are united," said the Bengal Chief Minister in what is seen as a reciprocation to the Congress support earlier this week.

"They (centre) are doing it deliberately ahead of the polls," Ms Banerjee added.

Though the ties between Rahul Gandhi and Ms Banerjee were seen as lukewarm, the Congress chief had dialled Kolkata when Ms Banerjee declared a sit-in protest against the Centre after what she called the "misuse" of the CBI.

On Sunday, officials of the Central Bureau of Investigation had knocked on Kolkata Police Commissioner Rajeev Kumar's doors to question him on "missing evidence" in the Saradha and Rose Valley chit fund cases. However, they were blocked by the local police and detained. The confrontation led to Ms Banerjee's three-day protest where she received support from several opposition leaders, including Aam Aadmi Party's Arvind Kejriwal, Samajwadi Party chief Akhilesh Yadav, BSP leader Mayawati and RJD's Tejashwi Yadav.

The opposition has accused the Centre of using central agencies for "political vendetta".

Robert Vadra was questioned for over four hours in a case involving purchase of a series of properties in the UK. Mr Vadra, who is also the son-in-law of Congress leader and UPA chairperson Sonia Gandhi, has said he is being subjected to "unwarranted, unjustified and malicious criminal prosecution" for political reasons.