THE soulful sound of koranic recitals for the dead reverberated from 22 homes lining a narrow, dimly lit street in the old Baghdad neighbourhood of Iskan in the early hours of yesterday morning.

In one house after another, the soothing voices mingled with the sobs of wives, mothers and sisters over a hum of visitors’ murmured condolences.

The walls of a small nearby mosque were draped with 22 black cloths on which the names of the husbands, sons and brothers being mourned will be inscribed in white paint, as is the custom in Iraq.

The grieving families in this predominantly Shi’ite district had collected their dead — all Sunnis — on Friday amid fury at the execution-style murders of the men and terror at the spread of sectarian killings in the run-up to this Saturday’s referendum on a new constitution.

Many believe the killers’ aim is to drive them out in a campaign of ethnic cleansing that is polarising communities, casting suspicion on the Iraqi police and undermining confidence in the ability of the Baghdad government to maintain security.

Some relatives of Iskan’s dead have already packed up and moved to Sunni areas where they feel safer.

The murdered men’s bodies were shrivelled beyond recognition when they were found where they had lain for a month in the desert more than 70 miles away, near the town of Badra.

But the blindfolds wrapped around their heads were intact, along with the cuffs of metal, plastic and rope used to bind their hands. One or two shots fired into each man had ended their lives.

“Why were they killed? What did they do?” shrieked one mourner as he prepared for a street procession of coffins to their place of burial on Friday.

The answer is difficult to discern. What is known is that all the Sunni victims were married to Shi’ite women. However, this is not uncommon in Iraq and is thought unlikely to be the motive for their murder.

One clue may lie in the alleged presence of Iraqi police officers when the men’s killers came to take them away. According to witnesses, about 40 police vehicles and four-wheel drives from the interior ministry stormed the district in the early hours of August 8.

The families say the police accompanied masked members of the Badr Brigade, the armed wing of Iraq’s main Shi’ite political party, the Supreme Council for the Islamic Revolution in Iraq. The Badr Brigade was funded, trained and equipped by Iranian Revolutionary Guards.

The raiders accused their targets of being Sunni insurgents or of helping the insurgency, although their families vigorously deny it.

Abu Baraa said that far from being an insurgent, his dead brother Najah al-Rassam, 37, had worked for the interior ministry’s Maghaweer special police force. This has led to speculation in the neighbourhood that the Badr Brigade wants to take over the special police and needed to get rid of a Sunni member. But nobody really knows why their street was selected by the death squad.

Abu Baraa was sleeping on the roof to avoid the stifling indoor heat of the summer night when the raid began.

“They dragged my brother Najah out of his bed, ignoring the pleas and cries of his wife,” he said. The couple had been married only three months.

A police commander is alleged to have asked a masked Badr representative whether Najah was “the wanted man”. The masked man replied: “Yes, sir, this is him.” A nod from the commander was apparently enough to ensure that Najah was hauled off. “This is state terrorism,” said Abu Baraa.

Major-General Adnan Thabit, commander of the interior ministry’s special forces, denied any government role in the slayings. He said fighters were dressing in police uniforms to inflame sectarian divisions.

Imad Hussam al-Deen, 42, a taxi driver and father of four, was also rounded up that day. His son, who refused to give his name, said his family had already left the neighbourhood.

“We have lost both my father and the sense of protection he extended to us,” he said. “God willing, I will avenge the death of my father and kill those bastards whose deeds have wiped the smiles from the faces of my mother, brothers and sisters.”

Just as Sunnis have fled a largely Shi’ite district, so many Shi’ites have left their homes in Sunni areas of Baghdad and in predominantly Sunni towns such as Ramadi, Falluja and Latafiya. The number is believed to be in the thousands.

Abu Haidar, a Shi’ite, lived until recently in a large house in the mainly Sunni Baghdad district of al-Doura. Shortly after four Shi’ite neighbours were killed, Abu Haidar, 45, who is married to a Sunni, received a warning from his wife’s family to leave the area because he had been targeted by insurgents.

He took his wife and six children and moved into a small house belonging to his in-laws.

“In the 1970s no one talked about Shi’ites or Sunnis — I don’t even think my father knew which sect he belonged to. In the 1980s, people became more aware of their sects as a result of the Iran-Iraq war. In the 1990s a person’s sect became more of an issue but in 2005 it all culminated in sectarian killings,” he lamented.

The bodies of at least 539 people who died violently have been found since April, according to a count by the Associated Press agency.

Shi’ites are now paying the highest price in blood. Last month Abu Musab al-Zarqawi, the Sunni leader of Al-Qaeda in Iraq, declared all-out war on them. But countless Sunnis are also terrified of death squads. The alleged acquiescence of the Shi’ite-dominated police has persuaded many to move into communities where they can be protected by their own.

For most of the families of Iskan’s 22 dead, however, leaving is out of the question because they are related to Shi’ites. Instead, they held a meeting with the Mahdi army of the Shi’ite cleric Moqtada al-Sadr and set up an armed force of their own to defend themselves against future raids.

The killings have deepened the Sunni-Shi’ite divide at a time when the country is already split over its proposed constitution. The minority Sunnis are being urged by their leaders to vote against it next weekend, arguing that it will lead to further fragmentation.

Amr Moussa, the head of the Arab League, announced yesterday that he would go to Iraq after the referendum in an attempt to reconcile the two communities. “The situation is so tense,” he said. “A civil war could erupt at any moment.”