He may, however, be again summoned to Shillong by the CBI after 20 February, sources said.
This on a day former Trinamool MP Kunal Ghosh prayed to the Barasat court for security saying that he perceived a threat to his life.
Ghosh, questioned in Shillong together with Kumar, had yesterday written to the CBI alleging that the police commissioner is trying to influence the probe.
Kumar, who had flown down to the Meghalaya capital on 8 February afternoon, landed back in Kolkata around 6 this evening.
His companions, additional commissioner Jawed Shamim and, deputy commissioner (Special Task Force) Murlidhar Sharma, have also returned by the same flight.
The Supreme Court had directed Kumar to appear for CBI questioning in Shillong and fully cooperate with the agency.
This after CBI had moved the apex court accusing the police commissioner of interference and trying to destroy evidence in the chit-fund scam probe.
This morning Kumar had gone to CBI office in Shillong for the fifth consecutive day but was allowed to leave around 12.30 in the noon. On the previous four days, he was questioned from morning to evening.
Meanwhile, former Trinamool MP Ghosh today prayed for security to Barasat court, where he turned up for a routine hearing in the Saradha chit-fund scam case.
An accused in the scam, Ghosh has spent three years in jail custody and is now out on bail.
“The names of several influential people cropped up during my questioning by the CBI in Shillong. The times have changed in Bengal: these days people are being shot dead right away. Hence, I have prayed to the court for security,” he told reporters at Barasat court.