He was convicted and sentenced to life imprisonment on sedition charges by the Additional District and Sessions Court at Raipur last month.
61-year-old Sen, a paediatrician by profession, was arrested in May 2007 in Bilaspur on suspicions of acting as a courier between Kolkata businessman Pijush Guha and alleged Maoist ideologue Narayan Sanyal. He was jailed for two years before the Supreme Court granted him bail in 2009.