MURDERERS on motorcycles are wreaking havoc in western Assam. At the end of July, four riders killed two Muslim men after an altercation at a mosque. This was the incident that sparked waves of killing between a tribal community, called the Bodo, and Bengali-speaking Muslims. Riots broke out soon after. In the beginning, armed Muslims riding motorcycles attacked a few Bodo villages, including Joypur in Kokrajhar district, where they killed four people. Soon enough, Bodos riding motorcycles were moving around in the same area, picking on Muslim targets. A Muslim pharmacy-owner was killed this week by three Bodo men on motorcycles, who fired as they sped past his shop. “These killers on motorcycles dodge the army and the police. They have become a terror,” says a local Muslim leader, Shariful Haque. Some large mobs were led by prominent Bodo leaders, including a lawmaker, Pradip Brahma. When the head of India’s governing party, Sonia Gandhi, visited camps that had been set up to house the displaced Muslims, wailing women complained to her about Mr Brahma. On August 23rd he was arrested and Assam’s state government imposed an indefinite curfew in the whole area, for fear of reprisals. More than 80 people, most of them Muslims but some of them Bodos, have been killed so far. Scores are missing and nearly half a million are homeless—again, more Muslims than Bodos. The army was called in to help, but even a month after the rioting erupted, reports of sporadic killings and arson are still trickling in. “This is now India’s worst internal displacement crisis but Assam is not getting the attention it deserves,” says Ranabir Sammadar of the Calcutta Research Group, a think tank.” Too many people have been made homeless in too short a time.” In the affected villages, life is not returning to normal. “We are struggling to survive here,” says Monowar Hussein as he moves about listlessly in the squalid, makeshift camp near Bilasipara town that houses 15,000 Muslims like him. “For food, for drinking water, for space to sleep, we are worse off than animals in barns.”

It is no different in the makeshift camps housing Bodos displaced by the violence. They want to go back home but are afraid to. “We are all traumatised over the events of July,” says Jhunu Boro, who came from Joypur village where the four young men were killed. “We thought we will be safe in the camps, but here we face survival problems.” “Houses have been razed to the ground, our fields have been damaged and our cattle hacked to pieces,” says Pramila Goyary of Gossaigaon village.

Militant Bodo groups have vowed not to let local Muslims return to villages that fall under the jurisdiction of the Bodoland Territorial Council, an autonomous body created seven years ago. “They [Muslims] will have to prove beyond doubt that they are Indian citizens before we allow them to come back,” says Govinda Basumatary, who heads a faction of a group called the National Democratic Front of Bodoland (NDFB). Mr Basumatary’s insinuation is that some or all of his Muslim neighbours are actually Bangladeshi nationals. Technically, the NDFB has been outlawed as a separatist group, but nevertheless one of its factions has been able to negotiate with the central government in New Delhi over a peace settlement for the past four years.

Under the terms of a ceasefire with Indian security forces, the NDFB is supposed to deposit all its weapons in designated camps. But the groups, now split into two factions, still have hundreds of armed fighters equipped with Chinese Kalashnikovs, grenades and even mortars. G.K. Pillai, a former home secretary of India, explains that “the whole Bodoland area is awash with illegal weapons. Nobody has done anything to check that and now we are paying the price.”

The Bodos, like the ethnic Assamese and other tribal groups in the north-east, resent encroachment by the Muslims, who are of ethnic-Bengali origin. The Bengali-speakers were first brought to Assam from what is now Bangladesh by the British, to cultivate the chars (river-islands) that are created each year by silt brought down by the vast Brahmaputra river. Their migration continued after the British left.

“The Congress [Party] encouraged the migration because they turned these settlers into solid vote-banks,” says Samujjal Bhattacharjee of the All Assam Students Union (AASU). “Now the indigenous people of Assam are all marginalised and these illegal settlers are taking over our lands, our sources of livelihood.”

The AASU ran a six-year campaign in the early 1980s to press for the detection and deportation of migrants. It paralysed Assam for months and led to a massacre in 1983. In one day, 1,800 Muslims of Bengali origin were slaughtered by Lalung tribespeople (also known as Tiwa) at a village called Nellie.

In 1985 the AASU signed an accord with Indian federal authorities, accepting those who came to Assam before March 1971 as legal immigrants, eligible for citizenship. Three decades later, most Assamese feel the 1985 accord solved none of their problems and failed to stop illegal immigration. Like the Assamese and the Lalungs, Bodo rebel groups have also periodically attacked Muslims and other non-Bodo minorities in western Assam. They would like to establish themselves as a majority, to support their demand for a separate homeland. In two phases in the 1990s, more than a quarter of a million people, mostly Muslims, were driven out and left to languish in makeshift camps.

After the Bodos won their autonomy and turned to enjoying the power that came with it, things seemed to returned to normal. But Assam’s Muslim population is increasing. Outside of Kashmir, no state in India is home to a higher proportion of Muslims; they now make up almost a third of Assam’s population.

But the conflict is not merely about religion. “It is as much about control over resources as about political power,” says Samir Das, who has studied Assam’s nativist movements. Since 2006 a Muslim-dominated party, the Assam United Democratic Front (AUDF), has increased its number of seats in the state assembly. Last year it managed to emerge as the state’s main opposition party, behind only Congress (which won by a landslide). Immediately after the AUDF’s success, some Muslim leaders raised a demand for a special administrative zone for their people in western Assam, where they outnumber indigenous peoples like the Bodos and the Rabhas.

“This newfound Muslim assertiveness is most evident in their strongholds in western Assam,” says Mr Das. “But that is also the area where tribes like the Bodos and the Rabhas want to enjoy self-rule in their exclusive homelands. Conflict is inevitable.”

After years of violent separatism, India’s north-east can ill afford another storm of ethnic and religious conflict. Even worse that it should be so near the “chicken’s neck”, a stretch of land just 20km wide that links the north-east with the rest of India. “All road and rail routes to the north-east pass through this strategic corridor and any trouble is bad news for our defence preparedness vis-à-vis China,” says Major General Gaganjit Singh, a former official in India’s military intelligence.

It threatens to spread beyond Assam into neighbouring Meghalaya and Nagaland. Tribal groups in those states are also demanding that illegal migrants from Bangladesh be kicked out. Both their governments have warned any potential vigilantes against taking the law into their own hands. But there too, as in Assam, tension is building up against members of a Muslim minority who are seen as “settlers”, sneaking into the voting rolls.

Tribal groups in Assam, Meghalaya and Nagaland all point to Tripura, once a tribal state ruled by a Tripuri king. Tripura’s tribes lost their majority share of the population as long ago as 1960, when Bengalis took their place. Tripura’s Bengalis are Hindus however, not Muslims, many of whom came to India as refugees, after Partition in 1947 and in the 1970s, during Bangladesh’s war of independence from Pakistan. “We don’t want to go the Tripura way,” says Joel Kath of the Naga Council, a vigilante group whose volunteers have threatened to deport “illegal Bangladeshi settlers” unless the government takes the initiative.