Standing in a large family house in the Hurriya district of Baghdad a little boy, no more than ten years old, with huge round eyes silently points out the bullet holes in each of the bedrooms. He goes from room to room, pointing out the marks in the wardrobe door, in the bed-frame, in the wall - he knows where they all are. It's the kind of knowledge no child should be burdened with.
Downstairs, six almost identical figures in black robes, sit in a row holding large pictures of their murdered men-folk, with a clutter of children on their laps.
These six women - all of them members of the same family, all of them recently widowed - have not been back into their bedrooms since last November, when a convoy of police cars drew up outside their home in the early hours and dozens of uniformed men burst in.
Another of the children, Hanin, was asleep in her parents' bed. She's almost matter of fact as she describes what happened next. 'I heard a gunshot so I cuddled my Dad. They came into our room and I told them not to kill my Daddy but the man threatened to shoot me. They shot Daddy and then they shot my Uncle.'
Five men were shot dead that night - a sixth had been killed in the street three weeks earlier. Their crime? The head of the family, Sheik Khadem Sarheed, was leader of a well-known Sunni tribe. Now he's dead, along with four of his adult sons and one son-in-law. One of the sons was a policeman and recognised the killers. 'He told them he was a policemen like them', says his widow, 'But they shot him in the neck and in the stomach'.
Neighbours saw the police cars parked outside the house and recognised the uniforms of the notorious police commandos. They're highly trained, heavily armed officers, more like soldiers than ordinary policemen. And they report directly to the Ministry of the Interior. Over the last eighteen months these commandos - who are almost exclusively Shia Muslims - have been implicated in rounding up and killing thousands of ordinary Sunni civilians.
Up to a hundred bodies a day are found dumped on waste ground and rubbish tips around Baghdad. They've usually been dreadfully tortured. Acid and electric drills are the favourite methods and many of the bodies are still wearing police handcuffs.
As we discovered, there is even compelling evidence that the secret prisons of Saddam's day are back - stinking hell-holes where hundreds of victims are herded together to be raped, tortured and maimed for no crime other than belonging to the wrong sect.
And it's all happening under the eyes of US commanders, who seem unwilling or unable to intervene. These are the chilling findings of a special investigation, filmed for a Channel 4 documentary, The Death Squads that reveals how one of the most senior ministers in Iraq's new administration stands accused of presiding over a campaign to torture, maim and execute his enemies. And this is the dossier that utterly explodes the myth that peace and a liberal democracy are blossoming in the new 'liberated' Iraq.
In the bloody mayhem of Baghdad it's very difficult to untangle exactly who's who amongst the various death squads who now rule the streets. There are organised criminal gangs, kidnapping and killing for ransom money, and there are private militia groups loyal to particular clerics or clan leaders. But there is no question that among the most efficient of the death squads are the police commandos.
As part of our investigation, we traced how these commando units have been deliberately infiltrated and taken over by one of the most militant Islamic groups, the Badr Brigade. They're the military wing of an Iraqi political party, The Supreme Council for the Islamic Revolution in Iraq. SCIRI was set up in the early 80's in exile in Iran and its aim was always to overthrow Saddam and his Sunni government and replace them with a Shia government. Now, very helpfully, the Americans have done that for them.
Immediately after Saddam was toppled in the Spring of 2003 thousands of Badr Brigade militiamen flooded back across the border from Iran, along with their political leaders who'd spent years waiting for this moment. They wanted the new Iraq to become a pro-Iranian, Islamic country where the Shia, who are 60% of Iraq's population, would also be the dominant political force.
They soon discovered that the best way to achieve this has been to inflitrate Iraq's new police force - right under the eyes the American administration.
From the early days of the US occupation of Iraq, the warning signs were there. One of the most senior British police officers sent to Baghdad was the former Deputy Chief Constable of South Yorkshire, Douglas Brand. His brief was very simple - to rebuild the Iraqi police. He wanted to create a professional force dedicated to law and order. But the Americans were so keen to build up the numbers they turned a blind eye to who was enlisting. 'They wanted to have the graduation parades, to have them in new uniforms', Douglas Brand told us. 'Nobody was too interested in what happened when they actually went out on the streets'.
Douglas Brand says he voiced his concerns, 'Probably ten times a day to whoever would listen, usually two star Generals and above.' He even spoke directly to the US Defence Secretary, Donald Rumsfeld, 'But I sensed the subtleties were not understood and if there were consequences down the road, that's something the Iraqis were going to have to handle themselves'.
Those consequences became clear very quickly. In June 2004 an American soldier, Kevin Maries, was looking through his sights of his sniper rifle from his usual position on the top floor of the Ministry of the Interior building when he saw Iraqi police commandos bring hundreds of prisoners into a Ministry compound directly below him.
He took a series of astonishing photographs through his rifle sight showing what happened. 'They were forced onto their knees, beaten with rubber hoses,' he remembers, 'The beatings got more severe, a metal bar was used and they were beating the soles of their feet'. When he thought some of the prisoners might die, Kevin alerted his unit and American troops turned up to stop the torture. But an hour later US Headquarters ordered them to withdraw and leave the prisoners to the mercy of their captors. As far as Kevin knows, most of the prisoners were later moved to an official prison but only after they were beaten again.
From the start the US authorities have been reluctant to interfere and that became even more marked when a controversial appointment was made to the Iraqi government. In May 2005, a man named Bayan Jabr was made Minister of the Interior - and thus the man in charge of the police. He was one of SCIRI's most senior figures.
Suddenly huge numbers of his own exclusively Shia militiamen from the Badr Brigade were recruited into the police. Gerry Burke witnessed that first hand. A senior Massachusetts policeman, seconded as a police adviser to Baghdad, Burke saw a memo from the new Minister authorising the recruitment of one group of 1,300 men into the Commandos without any obvious qualifications for the job. 'These were men without any police training, without any background checks', Gerry Burke told us, 'It was just changing uniforms from the Badr Brigade to the police'.
A few months later, when groups of Sunni men began to be kidnapped, murdered and their bodies dumped in the same spots every day, Gerry Burke tried to organise a surveillance operation to catch the killers. But the ordinary Iraqi police officers he was working with were too terrified to co-operate. 'They believed the perpetrators were members of the police who would have killed them in retaliation for investigating it'.
But that is by no means the only evidence that Iraq's Minsiter for the Interior is involved in a covert campaign of terror. One Iraqi MP, accuses Mr Jabr of being behind a network of secret prisons were Sunnis were held without charge and tortured. Of course, in a land where sectarian rivalries often involve wild allegations, we should treat any such claims with caution. But even with that in mind, the evidence provided to us by a Sunni MP named Mohammed al Dini is profoundly disturbing.
Last summer, Al Dini was among a delegation of MPs who turned up unannounced to check one of these suspected illegal sites. He showed us the video his staff took of the inspection. Several hundred men are pictured, crammed into cells. There are chaotic scenes of jubilation as the prisoners realise outsiders have come to end their ordeal and they all clamour to tell Al Dini their stories. One man is an Imam at a mosque. 'They forced us to talk by raping us', he tells the MP. Eventually prisoners sit patiently on the floor while one by one they display their injuries. Some have been branded with hot metal bars or had their fingernails ripped out. They lift their shirts to show bruises, scars and burns all over their bodies.
Then Mohammed Al Dini showed us a second video. Three days after he exposed this illegal prison, a group of his relatives visited him in Baghdad. On their way home their minibus was stopped by uniformed men. They were dragged out and executed on the street. The video shows ten bodies, lying on the pavement, in large pools of blood. Yellow leaflets have been scattered round which say, 'Congratulations to those who killed these Sunni extremists.'
Mohammed Al Dini is in no doubt about who murdered his ten cousins. 'They were militiamen operating as death squads inside the police', he says, 'And the attack was ordered by those people I exposed for running the prison.'
We interviewed Al Mohammed Dini in the safety of the Green Zone but he then made an extraordinary offer - to take us to his office and give us more evidence of police atrocities which have taken place while Bayan Jabr was the Minister in charge. His office was in a district called Yarmuk - a short journey but an incredibly dangerous one.
The general rule for Western journalists in Baghdad is to stay in the Green Zone - if you go anywhere else you need your own armed guards in armoured cars and you never stay anywhere for longer than ten minutes. Any foreigner venturing out runs the very real risk of being kidnapped by Sunni insurgents.
We discussed it as a team and took the advice of our calm and experienced security man, who's ex-British army. We decided to trust Mohammed Al Dini. We all climbed into his 4 x 4, with two of his own armed guards. As we drove through last checkpoint in the Green Zone and out into Baghdad's wild beyond a dozen more vehicles, four armed guards in each, were waiting.
They swung in to surround us. We were now in a huge convoy which included two pick-up trucks with men stood on the back manning machine guns. We drove past the Jihad district where last July the police and other armed gunman set up unofficial checkpoints. They inspected everyone's ID cards and executed more than forty people with Sunni names.
Then we went past Yarmuk hospital, which was surrounded by police cars. Iraqi hospitals are very dangerous places. We'd spoken to doctors who told us how patients, relatives and medical staff are regularly kidnapped from the treatment rooms by hospital guards and the police. Two doctors - too frightened to meet us - sent us emails. One said 'I'm writing to you crying with tears, they've gone on a wild rampage killing doctors'.
The second email, from a woman doctor, said 'These religious fanatics are killing the educated people so the country will be easier to be controlled.' A third doctor, who agreed to be in interviewed anonymously, described how an elderly woman was rushed in very ill. When the hospital guards realised she was the wife of a well known Sunni man they shot her.
There was more to come. When we reached Mohammed Al Dini's office, he handed over several CD's full of horrific images of corpses - victims, he claimed, of the death squads. 'Bullet holes?' I asked pointing to a picture of two round wounds. Mohammed Al Dini corrected me. 'No - electric drill holes'.
Then he fished out a five page document from his briefcase. It was a top secret report from Military Intelligence describing how they had caught eighteen policemen in the act of kidnapping two Sunni civilians. The police had confessed that they'd been ordered to pick up the men by their own senior officers who were members of the Badr Brigade. They were paid for each captive they handed over and they knew of at least nine men who'd later been found dead.
Mohammed Al Dini told me this all started when Bayan Jabr became Interior Minister - he was later promoted to Finance Minister, a role he continues to hold. 'There's a great deal of evidence against him, he's been involved in many human rights breaches in Iraq', he says.
Could it be true? Could one of the most senior figures in Iraq's new administration be presiding over a regime of terror every bit as savage as that under Saddam? We wrote to Bayan Jabr to ask for his response to all these allegations - but so far he hasn't replied.
One thing is for sure: life in 'liberated' modern day Iraq is every bits as terrifying as it was under Saddam - perhaps even more so. The videos that Mohammed Al Dini gave us were only part of a huge collection we built up during our time in Baghdad. Human rights organisations gave us hours and hours of material. One mass funeral after another, lines of coffins, crowds of wailing relatives.
But among the most heartbreaking tapes are ones the women in the 'House Of Six Widows' gave us. One shows the immediate aftermath of the killings - the Sheik and his sons covered in blood stained blankets. Another video is of the funeral.
But the third is quite different. The final video is from 2002, a year before the war began, and it shows the joyful scenes at a huge wedding of one of the sons - now murdered. The house where the Sunni family still live is in a mixed area and among the hundreds of friends and neighbours pictured dancing in the street with teh wedding party many were Shia. But since the coming of the death squads, many Sunni families have fled the area altogether. It's a pattern of ethnic cleansing being repeated across Baghdad as the city descends into ever deeper sectarian chaos.
It's impossible to work in Baghdad and leave with any ideas about simple solutions. Beware of anyone who offers them. The only certain thing is that tonight and every night for the foreseeable future, the death squads will be roaming the streets. And many of them will be so-called policemen.