The Supreme Court on Tuesday sought a response from the Enforcement Directorate (ED) on a plea by Karti Chidambaram challenging a summon issued to him in the INX Media money laundering case.A bench of Chief Justice Dipak Misra, Justice A.M. Khanwilkar and Justice D.Y. Chandrachud refused to grant protection against arrest by the ED, a plea strongly urged by senior counsel Kapil Sibal.While posting the matter for hearing on Thursday, the bench said that it would only examine the question of law raised by Sibal who appeared for Karti Chidambaram, the son of senior Congress leader P. Chidambaram.Addressing the court, Sibal said that the ED could not have acted against Karti without an FIR indicating whether the offence being alleged against his client was cognizable or non-cognizable.He told the court that Karti Chidambaram was being proceeded against by the ED for the same transaction under which the CBI has taken him into custody.Karti Chidambaram is currently in the custody of the CBI that is investigating allegations of his taking money for FIPB clearance to INX Media -- now renamed 9X Media -- when his father was Finance Minister.He has dubbed the allegations as "politically motivated".Karti Chidambaram was arrested by the CBI on February 28.