The uprising in Swat is a microcosm of Pakistan's war against militant Islam, writes Graham Usher in Islamabad Masked men with assault rifles and rocket-propelled grenades hauled four young policemen onto the village square, hands bound behind their backs. They were forced to their knees and then beheaded, one by one. "Let this serve as a warning to all those who spy for the government or help the government. All sons of Bush will meet a similar fate," said one of the masks. This is not Iraq or Afghanistan. It's the pastoral district of Swat in northwest Pakistan. It was once a flourishing tourist destination. It's become the latest front in an increasingly brutal war between the Pakistan army and an insurgent, militant Islam. The epicenter is Afghanistan and the Pashtun tribal regions that straddle its Pakistan border. But the conflict is gravitating inland. Swat is a three-hour drive from Peshawar. The beheadings were one response to the recent dispatch to Swat of 2,500 Pakistani soldiers, allegedly at the request of village elders. There were others. On 25 October a suicide bomber wrecked an army truck in Mingora, the district headquarters. Twenty people were killed, including 17 soldiers. The troops had come to quell the activities of Maulana Fazlullah, a local, pro- Taliban cleric. In the last year he has established "a parallel system of justice" in Swat, with courts, jails and, says the army, a 4,000-strong militia. The aim he says is to spread Sharia law. He has not yet declared jihad against the army but "in that case the situation will turn from bad to worse," warns a spokesman. The state -- police, local government and politicians -- has crumbled like sand before him. The army is the last line. Swat is a case study of the mutation of militant Islam in Pakistan -- and an illustration of why it poses such a threat. Fazlullah is the son-in-law of Maulana Sufi Mohamed. In 1994 he too tried to impose Sharia law in Swat. The army took 12 days to crush him. In 2001, he levied 10,000 men to fight the US-led invasion of Afghanistan "in the manner of the prophet" i.e. on horseback and with swords. They were mown down in the manner of the American army, i.e. by machine gun fire. On his return to Pakistan Mohamed was jailed and his Tahreek Nifaz-e-Shariat Mohamedi (TNSM) movement banned. But the son-in-law was allowed to preach. He did so through his own FM radio station, a crucial medium in an area where most cannot read and many don't have television. He decreed the education of girls to be un-Islamic. He also said polio drops delivered by an international NGO was an American plot to rob Muslims of their potency -- with the result that polio rates climbed in Swat for the first time in a decade. Finally, he Arabised the names of villages, so that many no longer could say where they lived. Some turned to his system of justice -- largely because there was no other. But most loathed his destruction of what had been a hybrid culture and a thriving tourist industry, the principle source of jobs. But with a venal, useless police force few dared challenge him. And the government appeased him. Despite the ban on his organisation, in May it negotiated a deal -- Fazlullah should keep his radio station if he dropped the campaigns against polio vaccination and female education. Local politicians said he was a "freak" (their word) but a harmless one, certainly when compared with Al-Qaeda and the Taliban on the Afghan border. That casualness ended in July, after army commandos stormed Islamabad's Red Mosque, led by another pro-Taliban cleric, Abdul-Rashid Ghazi. More than 100 died, and Fazlullah swore revenge. Since then, scores have been killed, including nearly 50 soldiers, in dozens of suicide and roadside bomb ambushes in Swat. Locals doubt this is the work of the TNSM. They suspect rather the Taliban from the tribal regions or Uzbek fighters once linked with Al-Qaeda. There have also been sightings of Jaish Mohamed (JM) -- a ruthless jihadist outfit that introduced suicide bombings to the struggle in Indian Kashmir. It these that are behind the suicide attack, beheadings and cultural vandalism, like the recent desecration of Buddhist statues in Swat, say locals. But what do the militants want? The Taliban's aim is territorial, says a journalist who recently spent time with its leadership on the Afghan border. "The Taliban is invading Swat because the army invaded the tribal areas. If the army leaves, so will they. The priority for them remains the insurgency in Afghanistan," he says. But another journalist detects a darker, less tactical purpose. She says the presence of the JM and Uzbeks means the goal is ideological. It reminded her of the Taliban regime in Afghanistan. "In 1999 Mullah Omar said he would protect the Buddhas at Bamyan. They were part of the Afghan heritage, he said. In 2001, he blew them up. What happened? Osama bin Laden and Al-Qaeda had happened. I see the same thing in Swat." Another similarity is the army's response. So far it has consisted of sporadic, uneasy ceasefires combined with bombardments of mountains, valleys and villages. Hundreds of civilians are taking the road to Peshawar with not much else than the clothes they wear. "We felt so helpless," said one. "There is fear and gloom in the village."