The CBI has summoned Commonwealth Games Organising Committee Chief Suresh Kalmadi to appear before it for interrogation relating to alleged financial irregularities in the conduct of mega sporting event. AIR correspondent quoting CBI sources reports Mr Kalmadi has been served a notice in this regard and the agency has taken necessary permission from Lok Sabha Secretariat. Mr Kalmadi is a member of the Lok Sabha. Sources say, Mr Kalmadi is likely to appear before CBI in the first week of January.CBI sleuths have also grilled Mr Kalmadi's three key aides in connection with the financial irregularities.