The Central Bureau of Investigation (CBI) wanted the death sentence for Singh, who was linked with Hindu right-wing group Bajrang Dal.
The Staines family was burnt alive in Keonjhar. Graham Staines had worked with leprosy patients in Orissa for 30 years. He was sleeping with his sons, aged 8 and 10, in a car on their way home on a cold January night. A mob in Manoharpur village poured petrol over the Staines' car and set fire to it.
The Staines tried to escape, but a mob of about 50 people allegedly prevented them.
In 2003, a trial court in Khurda convicted all 13 accused. While Dara Singh was awarded the death sentence, the others were sentenced to life in prison. In 2005, the Orissa High Court commuted Singh's sentence to life. The High Court convicted Hembram along with Singh, and acquitted 11 others.
The Supreme Court said today, "We hope Mahatma Gandhi's vision of religion playing a positive development integrating into a prosperous nation will be realized. There is no justification from interfering in someone's belief through force, conversion or false premise that one religion is better than the other."
Reacting to the court's verdict and comments, Father Babu Joseph, spokesperson for the Catholic Bishops Conference of India, said, "We accept it (the verdict) as the outcome of years of legal procedure. Two innocent children and father were killed in a brutal manner. They were serving lepers for many years. The allegations made that they were involved in religious conversions were utterly baseless. It's a serious reminder that there are organizations in this country operating with a hate agenda which want to create hate between different communities." He also stressed that all religious groups have the constitutional right to propagate their religion.