Shillong, Feb 9 (IANS): The Central Bureau of Investigation (CBI) on Saturday began questioning Kolkata Police Commissioner Rajeev Kumar in connection with the chit fund case, an official said.

"They (CBI) have started interrogating Kumar in their (CBI) Shillong branch office since 11 a.m. on the matter," an official told IANS on the condition of anonymity.

Kumar arrived at the office at Oakland here at 10.45 a.m.

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.

He was accompanied by three West Bengal cadre IPS officers and his younger brother, the official said.

A CBI team was allegedly roughed up and detained for a few hours when it went to question Kumar at his residence in Kolkata on Sunday in connection with its probe into the Saradha and Rose Valley chit fund cases.

Following the face-off between the CBI and Kolkata Police, West Bengal Chief Minister Mamata Banerjee staged a sit-in protest for over 45 hours.