Police in India have arrested 47 people and are looking for more in connection with a horrific killing. An Australian missionary and members of his family were killed in an apparent act of religious violence.

Police say Graham Stewart Staine and his two sons, ages 10 and eight, were sleeping in their jeep in Eastern India when an angry mob set it on fire. All three were burned to death. The village church was also burned down.

Staine had been working as a Christian missionary in India for the last three decades, working among tribal peoples and lepers.

Many of the suspects are members of a radical Hindu group. The group denies any involvement.

Christian missionaries have come under attack from alleged Hindu right-wing activists in recent months. Churches have been burned and dozens of priests and nuns have been injured. No one has claimed responsibility for the violence.

Hindu extremists say the Christians are forcefully converting the poor. The Christians deny that, saying they are only offering charity.

Christians make up a little over two per cent of India's nearly 1 billion population, while Hindus account for more than 80 per cent.