The CBI has arrested a top official of the public sector National Buildings Construction Corporation (NBCC) for allegedly receiving a bribe of Rs 4 lakh for clearing bills worth over Rs 24 crore. The arrested accused Utpal Paul, Deputy General Manager (DGM), NBCC, had initially demanded a bribe of Rs 50 lakh from a businessman, about two per cent of the total pending bills, sources said. As first installment, he had sought Rs 10 lakh but the businessman negotiated and brought the amount down to Rs 4 lakh. Paul was arrested on Thursday night by the CBI in Guwahati, Assam, while receiving the payment, they said, adding other senior officers of the NBCC, Guwahati, are also under the scanner of the agency.