In a huge embarrassment for Chief Minister Mamata Banerjee, the Supreme Court has ordered a CBI probe into the Saradha chit fund scam that Narendra Modi, the BJP's prime ministerial candidate, has turned into the main issue in his poll campaign in West Bengal. The collapse of Saradha last April robbed lakhs of people of crores of rupees. One Trinamool MP is in jail and some other party leaders, too, are believed to have links with Saradha. The Opposition welcomed the top court's ruling. So did Ms Banerjee's Trinamool Congress, but added that the order comes just two days before 17 seats go to polls on Monday.