"It is scandalous to say that he (Sen) was working against the interest of the country. The Unlawful Activities Prevention Act under which he has been convicted is unconstitutional," Sachar said in a statement here.
The PUCL will challenge his conviction and the Act, he said, adding the judgement conviction of Sen was "outrageous".
Sen, Naxal ideologue Narayan Sanyal and Kolkata businessman Piyush Guha were today convicted for sedition and sentenced to life imprisonment for colluding with Maoists to establish a network to fight the state.
58-year-old Sen, a paediatrician by training and vice-president of People's Union of Civil Liberties, had been accused by the prosecution of acting as courier for Sanyal, who was in jail, by carrying his messages and letters to the underground Maoists.
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