Dr Binayak Sen, who spent two years in an Indian prison as a Prisoner of Conscience, was released on Tuesday after being granted bail by the Supreme Court.
Welcoming Dr Sen's release on bail, Amnesty International believes that the charges against him are baseless and politically motivated. Amnesty International has repeated its call on the Indian authorities to immediately drop all the charges against Dr Sen.
Dr Sen, who was held in Raipur prison in the central Indian state of Chhattisgarh, thanked Amnesty International and other human rights organizations that have been campaigning for his release. He said he would continue to defend human rights in Chhattisgarh despite possible threats to his life from "state and non-state actors".
The 59-year-old is a pioneer of health care to marginalized and indigenous communities in Chhattisgarh, where the state police and armed Maoists have been engaged in clashes over the last six years.
He was arrested on 14 May 2007 on politically motivated charges, aimed at stopping his human rights work, after he met with an imprisoned leader of a banned Maoist organization.
His earlier meetings with an imprisoned Maoist leader, on which some of the charges against him were based, had all been facilitated by the prison authorities.
"Dr Sen's prolonged imprisonment is a glaring example of how the Indian authorities misuse security legislation to target activists," said Madhu Malhotra, Deputy Director of Amnesty International's Asia-Pacific Programme.
"These laws are open to abuse as they contain vague and sweeping definitions of 'unlawful activities'. Under no circumstances should work that peacefully defends human rights be termed an 'unlawful activity'."
Prior to his arrest, Dr Sen had criticized the state authorities for enacting special security legislation - the Chhattisgarh Special Public Safety Act, 2005 (CSPSA).
He had also reported on unlawful killings of adivasis (Indigenous People) by the police and by Salwa Judum, a private militia widely held to be sponsored by the state authorities to fight the armed Maoists.
The state authorities have so far failed to conduct effective and impartial investigations into these unlawful killings.
Dr Sen was detained without proper charges for seven months, denied bail, and kept in solitary confinement for three weeks. Many of the charges against him stem from laws that contravene international standards. Repeated delays in the conduct of his trial have also heightened doubts about its fairness. Meanwhile, Dr Sen had asked for specialist medical treatment for his heart ailment.