West Bengal Chief Minister Mamata Banerjee on Thursday termed as "shameful" the Centre's statement that documents related to the Rafale fighter jet deal have been stolen and demanded a probe."It is a matter of shame. We haven't seen anything like this before. If documents can get stolen from an important Central government department, then don't you guys think that the nation is in deep trouble?" Banerjee said at the state secretariat Nabanna."It is a very serious matter and I think there must be an investigation," she said."What sort of nuisance is going on in the country, that documents are being stolen from the Defence Ministry?" Banerjee had tweeted earlier.Claiming that the Centre had no remorse for losing the documents related to country's security, Banerjee questioned if the current government is capable of maintaining the sovereignty of the country."If documents related to our country's internal security could get stolen like this, then how will the sovereignty and security of our country be maintained?" she asked."They are announcing with pride they have lost (the documents). What can be more dangerous than this? If documents are stolen from a central government department, it is their responsibility," Banerjee added.