Kumar, who headed the Special Investigation Team (SIT) of the state police department that initially probed the scam, reached the Central agency's Kolkata Office at the CGO Complex here around 10.30 a.m.
He left the agency office around 3 p.m.
The CBI had earlier interrogated the senior officer in the case in Shillong back in February under directions of the Supreme Court which recently asked him to cooperate with the probing agency.
According to agency sources, the entire interrogation process was video recorded and Kumar's statements will be matched with another Bengal IPS officer Arnab Ghosh, who was recently grilled by the CBI in the same case.
Kumar, currently posted as the Additional Director General of the West Bengal CID, has been summoned multiple times by the CBI sleuths in recent weeks but failed to appear as he said he was on leave.
The investigative agency had issued a lookout notice for Kumar last month directing all airports and immigration authorities to alert it if they spot him leaving the country.
Following this, Kumar moved the Calcutta High Court seeking quashing of the CBI notice against him.
The court granted him protection from coercive action till July 10, but asked him not to leave Kolkata and cooperate with the agency in the ongoing probe.
The CBI is seeking custodial interrogation of Kumar as it believes that certain documents seized by the state police's SIT during the initial stages of investigation into the Saradha scam, were not handed over to them.
( With inputs from IANS )