Human rights activists said they were stunned after an Indian court Friday sentenced rights campaigner and public health expert Binayak Sen to life in prison after finding him guilty of helping Maoist rebels, dpa reported. A lower court in the central state of Chhattisgarh found Sen guilty of sedition and conspiracy, the IANS and PTI news agencies reported. Sen, who has spent a quarter-century practising medicine among tribal people of Chhattisgarh, was arrested in 2007 for his alleged links with the Maoists. A recipient of the Global Health Council's Jonathan Mann Award for Global Health and Human Rights in 2008, Sen was released on bail in May 2009 after spending two years in jail. "I am shocked by this judgement," said Mahipal Singh, secretary of the People's Union For Civil Liberties. "There is absolutely no evidence against Binayak Sen. How can a human rights activist be sentenced like this? It's a sad day for our democracy." Sen, who is a vice president of the rights group, was accused of helping the Maoists and of carrying letters to and from Narayan Sanyal, a jailed Maoist leader. Sanyal was also found guilty of sedition Friday and sentenced to life imprisonment along with Kolkata-based businessman Piyush Guha, also accused of links with the rebels. During court proceedings in 2009, Sen said he did not support the Maoists. He has, however, often criticized the government for its handling of the Maoist rebellion and for neglecting development in tribal areas.