New Delhi, Nov 13: BJP today asked Congress President Sonia Gandhi to advise her party chief ministers to accept a CBI probe into the Rs 30,000 crore stamp paper scam since it has links not only in about ten states in the country but also abroad. "This scam has occurred with the connivance of state ministers as also senior officials in various states and a CBI probe would help bring out the truth in the case," party spokesman Mukhtar Abbas Naqvi told reporters here. He said this being the biggest scam since independence and spread in about ten states "the truth cannot be brought out by state agencies and therefore CBI probe is essential so that everything comes out clearly." Naqvi accused the Congress of "shamelessly" trying to save its ministers involved in this stamp paper scam and this is also on in the four Congress-ruled states of Rajasthan, Madhya Pradesh, Chattisgarh and Delhi where elections are slated for December one. Bureau Report