The murder squad struck swiftly, emerging from the jungle in the dead of night. At around 2am, about twenty Maoist guerrillas crept into the village of Rudigumma, a clutch of mottled huts deep in the remote eastern Indian state of Orissa. Silently they encircled the house of a worker for the Rashtriya Swayamsevak Sangh (RSS), India's most powerful extremist Hindu group.

Their target, Prabhat Panigrahi, an RSS leader who had been released from prison five days earlier after being accused of inciting religious violence last year, was shot in the back and killed as he scrambled to escape.

The murder in March, its clinical precision a hallmark of India's Maoists, marked the most recent clash between two groups bent on remaking the country. On one side stands the extreme Hindu Right, which wants to expel Western influences and transform India into a caste-based theocracy. On the other the atheist communists, who dream of class war, boast a 10,000-strong guerrilla army and are growing more audacious by the day.

Both groups seem to be using Orissa, a poor state that has become a focus for this month's Indian general election because of its bloody recent past, as a laboratory to test their ideas. The most frightening implications of their experiments are for a third community: the region's minority Christians, who are caught in the middle.

The murder of Panigrahi carried a chilling echo of an earlier Maoist operation in the area, the killing of Swami Lakshmanananda Saraswati, another Hindu hardliner accused of oppressing Christians, last August.

After Hindu extremists blamed Christians for the crime, a retaliatory wave of murder, arson and rape forced 50,000 Christians to abandon their homes. As many as 200 people were killed, according to church groups.

The bleakly beautiful countryside of Kandhamal, the district of Orissa that suffered the worst unrest, remains dotted with ruined Christian villages and charred churches.

The vast majority of those who were forced to flee are yet to return. They include Asmith Digal, a young mother of two who lives in the Mondakia refugee camp, a collection of bedraggled tents guarded by a handful of paramilitary police that house about 1,500 Christians.

She told The Times that her husband, Rajesh, was buried alive last summer by a rampaging Hindu mob. His body was never recovered and no police case was registered.

There are scores of similar stories.

Many refugees have fled Orissa. Thousands of others, such as Sonorani Pradhan, 70, live in tarpaulin bivouacs close to the shells of their wrecked homes. “I have nothing, no family to look after me, no money, no job, and the Government has not even given me a tent,” she said.

Many say that they have been ordered to stay away from their homes and fields until they convert to Hinduism. The plight of Orissa's Christians, most of whom come from Dalit (“Untouchable”) communities that were downtrodden for millennia under India's caste system, has not escaped the Maoists. “They come here to recruit,” confides one Christian villager, keeping his voice low for fear of police spies.

The Maoist movement, which has been identified as the No 1 security threat to the country by the Government, has prospered most in areas of India most seriously blighted by poverty and social injustice, experts say.

The chance of fresh violence in Orissa appears high - not least because the Maoists recently released a list of 15 names, including several hardline Hindus, whom they have promised to kill in the same manner as Saraswati. In Kandhamal, one of the candidates for the Hindu nationalist BJP - India's main opposition party - in the general election faces charges of instigating last year's violence. Manoj Pardham is yet to be tried and is campaigning from prison.

Meanwhile, stuck in the middle, the Christians suggest that they have few options other than prayer.

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