With underworld don Abu Salem, one of the key accused in the 1993 serial blasts in Mumbai, deciding to contest assembly polls in Uttar Pradesh, the Central Bureau of Investigation (CBI) is set to cut short his political ambitions by citing the prison term served by him in Portugal before his extradition to India.Lodged in judicial custody since he was sent back from Lisbon on November 11, 2005 with girl friend Monica Bedi, Salem had given indications about contesting the assembly elections scheduled for April or May.Pre-empting his political aspirations, the CBI is set to write to the home ministry to prevent any such move by the underworld don as he was convicted in Portugal and served a prison term of over three years in Lisbon, agency sources said.A draft had been finalised in which the CBI will draw the ministry's attention to the prison sentence served by Salem, they said.The question whether Salem's conviction abroad can bar him from contesting polls needs a thorough discussion and the CBI is hoping that this starts soon rather than at a point when he gets his papers filed before the returning officer for his consituency, the sources said.Under the law, no convicted person can contest elections.PTI