CBI sources said a notice has come to the agency through the office of Chairman, Rajya Sabha claiming the searches at his home and office were breach of his parliamentary privileges.
Bandopadhyay did not responded to the smses seeking his reaction.
Highly placed sources in the agency, however, defended their actions saying the searches at his residence were after taking necessary permissions and in accordance with the rules and regulations laid down.
CBI has named six -- three former and three sitting -- members of Rajya Sabha for allegedly filing inflated travel bills to claim the reimbursement. The agency had carried out searches at their residences after registering cases against them.
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Bandopadhyay was examined by the agency on June 16 at the CBI headquarters after which he had claimed that he was satisfied with the probe and described CBI as the "civilised bureau of investigation".
CBI has alleged that Bandopadhyay had presented four tickets worth Rs 1.28 lakh whereas actual payment of Rs 2,000 was made to Air India thus making a gain for Rs 1.26 lakh for himself on the inflated bills.
Besides Bandopadhyay, CBI has registered cases against two other sitting MPs Brajesh Pathak of BSP and Lalhming Liana of Mizo National Front and three former Rajya Sabha members JPN Singh (BJP), Mahmood A Madani (Rashtriya Lok Dal) and Renu Pradhan (Biju Janata Dal) in connection with the case.