The CBI alleged that Rajeev Kumar tampered with the electronic evidence in the Saradha scam.

The CBI has attached ten officers from its Delhi, Bhopal and Lucknow units to its Kolkata office, which is probing the chit fund scam cases, till February 20 to provide additional manpower during questioning of some high profile suspects, including Kolkata police commissioner Rajeev Kumar, officials said.

A team of Superintendent of Police or SP Jagroop S Gusinha from its Special Unit in New Delhi accompanied by Additional SP V M Mittal, Surendra Kumar Malik, Chander Deep, Deputy SPs Atul Hajela, Alok Kumar Sahi and P K Srivastava, Inspectors Hari Shankar Chand, Ritesh Danhi and Surajit Das will camp in Kolkata, an official order said.

It said these officers will be temporarily attached to CBI, EO-IV, Kolkata. They have been asked to reach Kolkata by Friday and will be stationed tentatively up to February 20.

"Decision to issue notice to Kumar on a given date will be taken by investigation officer of the case," a senior official said.

The Supreme Court on Tuesday directed Kolkata Police Commissioner Rajeev Kumar to appear before the CBI and "faithfully" cooperate into the investigation of cases arising out of the Saradha chit fund scam, while making it clear that he will not be arrested.

The apex court had said that "to avoid all unnecessary controversy", it is also directing the Kolkata Police chief to appear before the investigating agency in Shillong, a neutral place, on such dates as may be fixed by the probe agency.

During the hearing, the CBI had alleged total breakdown of constitutional machinery in the state by citing the incident of Sunday when the city police had taken into its custody around 25 personnel of the agency.

They had gone to Mr Kumar's residence to probe him in the Saradha scam.

The CBI alleged that Mr Kumar, who was leading the SIT probe into Saradha chit fund scam, tampered with the electronic evidence and handed over documents to the agency some of which were "doctored".

The CBI team, which had reached Mr Kumar's residence on Sunday evening to apparently question him in connection with Saradha and Rose Valley scam cases, was caught off guard when they were blocked by police personnel guarding the residence in central Kolkata's Loudon Street, officials said.