"I cooperated with the CBI during their course of examination. I will continue to cooperate with them)," Ghosh said after emerging out of the CBI office.
The former Rajya Sabha member, arrested on November 2013 in connection with the two chit fund scams and granted interim bail by the Calcutta High Court in 2016, said: "I am going back to Kolkata tomorrow (Tuesday)."
Ghosh had earlier implicated former Union Minister Mukul Roy, who has quit the Trinamool Congress to join the Bharatiya Janata Party, and 12 others in the Saradha chit fund scam.
On Saturday, the CBI interrogated Kumar for eight hours on charges of withholding and tampering important documents.
Kumar arrived in Shillong on Friday evening from Kolkata via Guwahati after the Supreme Court, while hearing the matter on Tuesday, directed him to join the CBI probe at a "neutral place" in Shillong.
He was accompanied by three senior state police officers - Additional Police Commissioner Javed Shamim, Special Task Force chief Murlidhar Sharma and CID chief Praveen Kumar Tripathi.