DMK president M. Karunanidhi Sunday demanded that authorities reveal the Indian politician's name with whom arrested Sri Lankan national and alleged spy Arun Selvarajan had connections.Referring to the arrest of Selvarajan, who was spying at the instigation of Pakistan, by the National Investigation Agency, Karunanidhi said: "There are reports he was in contact with a politician. Who is this politician should be made public."He said this is not the first time an anti-national was arrested in Tamil Nadu. He said Pakistani spy Thameem Ansari was arrested last September in Trichy while Sri Lankan Zakir Hussain and his associates Salim, Sivabalan and Rafique were arrested in April this year.Karunanidhi also said the case of the twin bomb blasts in the Bangalore-Guwahati tri-weekly express train that killed a woman passenger and injured many others at the Chennai Central station May 1 is yet to be solved.