GILGIT, PAKISTAN // About 20 men dressed as Pakistani soldiers boarded a bus bound for a Muslim festival outside this mountain town and checked the identification cards of the passengers. They singled out 19 Shiites, drew weapons and killed them.
The shooters were not soldiers. They were a hit squad linked to the Sunni extremist group Lashkar-e-Jhangvi, or LeJ. They had trekked in along a high Himalayan pass that hot morning in August to waylay a convoy of pilgrims.
Here and across Pakistan, violent Sunni radicals are on the march against the nation's Shiite minority.
With a few hundred hardcore cadres, the highly secretive LeJ aims to trigger sectarian violence that would pave the way for a Sunni theocracy in the country, say Pakistan police and intelligence officials. Its immediate goal, they say, is to stoke the intense Sunni-Shiite violence that has pushed countries like Iraq close to civil war.
More than 300 Shiites have been killed in Pakistan so far this year in sectarian conflict, according to human rights groups. The campaign is gathering pace in rural as well as urban areas such as Karachi, Pakistan's biggest city. The Shiites are a big target, accounting for up to 20 per cent of this nation of 180 million.
In January, the LeJ claimed responsibility for a homemade bomb that exploded in a crowd of Shiites in Punjab province, killing 18 and wounding 30. Its reach extends beyond Pakistan. Late last year, it claimed responsibility for bombings in Afghanistan that killed 59 people, the worst sectarian attacks since the fall of the Taliban government in 2001.
"No doubt - [LeJ] are the most dangerous group," said Chaudhry Aslam, a top counter-terrorism police commando based in Karachi, whose house was blown up by the LeJ. "We will fight them until the last drop of blood."
For an outlawed group accused of fomenting such mayhem, the leader of LeJ is surprisingly easy to find.
Malik Ishaq spent 14 years in jail in connection with dozens of murder and terrorism cases. He was released after the charges could not be proved - partly because of witness intimidation, officials say - in July last year.
Although Ishaq is one of Pakistan's most feared militants, he enjoys the protection of followers clutching AK-47 assault rifles in the narrow lane outside his home in the town of Rahim Yar Khan, in southern Punjab province.
"The state should declare Shiites as non-Muslims on the basis of their beliefs," said Ishaq, calling them the "greatest infidels on earth".
In interviews, police, intelligence officials, clerics and LeJ members described a group that has grown more robust and appears to be operating across a much wider area in Pakistan than just a few years ago.
The LeJ once enjoyed the open support of Pakistan's powerful spy agency, the Directorate for Inter-Services Intelligence. The ISI used such groups as military proxies in India and Afghanistan and to counter Shiite militant groups.
Since being outlawed after the attacks of September 11, 2001, LeJ has worked with Al Qaeda and the Pakistani Taliban in several high-profile strikes, including assaults in 2009 on Pakistan's military headquarters and on Sri Lanka's visiting cricket team. Washington says LeJ was involved in the killing of the Wall Street Journal correspondent Daniel Pearl in 2002.
When the Taliban and Al Qaeda want to reach targets outside their strongholds on the Afghan border, they turn to LeJ to provide intelligence, safe houses or young volunteers eager for martyrdom, police and intelligence officials said.
"Lashkar-e-Jhangvi is the detonator of terrorism in Pakistan," said the Karachi police superintendent Raja Umer Khattab, who has interrogated more than 100 members. "The Taliban needs Lashkar-e-Jhangvi. Al Qaeda needs Lashkar-e-Jhangvi. They are involved in most terrorism cases."
Now the group gathering strength anew. The risks are heightened by Pakistan's long-standing role as a battlefield in a proxy war between Sunni Saudi Arabia and Shiite Iran, which have been competing for influence in Asia and the Middle East since the 1979 Iranian revolution. Intelligence officials say the LeJ is drawing financial support from Saudi donors and other Sunni sources.
"Unfortunately, the state for strategic reasons turned a blind eye to the LeJ for a long time," said a retired army general. "Now we have a situation where it has become Pakistan's Frankenstein."
What makes LeJ particularly dangerous is that the group is based in Pakistan's Punjab heartland. And it is not just attacking targets in Pakistan's neighbours, but has also targeted the state, including the 2009 attack on Pakistan's military headquarters.
The LeJ was established as an offshoot of another anti-Shiite organisation called Sipah-e-Sahaba (SSP). It believes it has a sacred calling - to protect the legacy of the companions of the Prophet Mohammad - and it sees Shiites as the main threat.
Hardline Sunnis believe that Iran is trying to foment revolution in Pakistan to turn it into a Shiite state, though no evidence for that is offered.
Some Shiite groups do look to Iran's clerical establishment for spiritual leadership, but insist they have no aims beyond protecting members from Sunni attacks.
Shiite leaders say they are urging young men to exercise restraint and buy weapons only for self-defence.
"We are controlling our youth and stopping them from reacting," said Syed Sadiq Raza Taqvi, a Karachi cleric.
But with each killing, the temptation to take revenge grows.
The massacre of Shiite bus passengers outside Gilgit has had a profound impact on this mountaineering hub in the Himalayan foothills.
Sunnis and Shiites, who had lived in harmony for decades, now cope with sectarian no-go zones.
"Sunnis can't go to some areas and Shiites can't go to others," said Muneer Hussain Shah, a Shiite shopkeeper whose brother was killed in a grenade attack.
When violence erupts, text messages circulate rallying one sect or the other. Shops and schools close. Authorities have banned motorcycles to stop drive-by shootings.
Law enforcement itself is a victim of sectarianism in Gilgit, said the police chief, Usman Zakria. Shiite officers are reluctant to investigate crimes committed by Shiites, and the same is true of Sunnis.
"They are in disarray," said Mr Zakria. "None of this has happened before."