Biswal, who was taken on remand by the CBI on September 20, was produced before the special CBI court yesterday, a day before his remand period was to end, and the probe agency told the court that the MLA's interrogation was over.
Following this, the court sent Biswal to jail.
It had ordered the jail authorities to conduct a medical check-up of the legislator after his lawyer Anup Senapati informed the court that his client should be shifted to a hospital due to his post-operative illness.
The CBI, probing the multi-crore Seashore Group chit fund scam, had called Biswal, a three-time MLA, to its office here on September 18 and subsequently arrested him.
The investigating agency is probing alleged payment of Rs 25 lakh by Seashore Chairman cum Managing Director Prasanta Kumar Dash to Biswal in two instalments as "protection money" for allowing smooth operations of the company in his constituency, CBI sources had said.