The father-son duo are in the radar of the probe agencies in another case concerning the Aircel-Maxis deal.
The Central Bureau of Investigation had called Karti for questioning on Thursday in connection with the foreign investment clearance given in the Aircel-Maxis deal in 2006 when his father Chidambaram was the finance minister.
Karti, through his lawyer, has refused to appear before the agency saying a special court had discharged all the accused in the matter.
The sources said the matter should have been referred to the Cabinet Committee on Economic Affairs as foreign investments above Rs 600 crore (Rs 6 billion) can only be cleared by Cabinet Committee on Economic Affairs headed by the Prime Minister.
Chidambaram was competent to give approval of upto Rs 600 crore but he gave the approval which was worth approximately Rs 3,500 crore