Another 'normal' day in Iraq, as armed Mahdi Army militants parade through Baghdad's Sadr City district.
[Photo: Kareem Raheem/Reuters]

A muscular, 45-year-old Shia, Abu Karar is the intelligence officer in the Martyr al-Sadr office, the organisation led by Moqtada al-Sadr, in a Shia district in the south of Baghdad.

Until recently, the industrial neighbourhood of mechanic shops and spare parts dealers was a mixed Shia-Sunni area. But through a campaign of intimidation, kidnappings and assassinations, Shia militias drove most of the Sunnis out. Abu Karar was one of those in charge of the "cleansing campaign".

A former officer in Saddam's army, he drives around the area in a Japanese car, visiting his men at their checkpoints, talking to police officers and answering numerous calls on his two mobiles.

"I have men everywhere," he says, "ready for any attack from them." In Abu Karar's world, them means Sunni insurgents. The structure of the Jaish el-Mahdi (the Mahdi army) differs from the militia that fought the US and British two years ago. The mainstream Mahdi militia has become much more organised and complicated. At the same time, there is evidence that some commanders are working independently. With the average ransom for a hostage around $5,000 (£2,635) and sometimes up to $20,000, running a militia in Iraq these days can be a very lucrative business. But Abu Karar dismisses suggestions that his men are involved in death squads. "We are defending our people. If the Sunnis come from an area to attack us, we go and attack them. They have started this fight." The mainstream Mahdi militia is organised around the Martyr al-Sadr offices, scattered around Baghdad and holding more authority, in some areas, than the government...

The Mahdi army models itself on Hizbullah, the Lebanese resistance organisation, he says. "We are not only an army for killing, we provide services. We get gas cans from the plant and deliver it to the people. We give the people what the government is unable to provide: services and protection." If someone wishes to inform on a "terrorist", they are asked to swear on the Qur'an. The rest is taken care off by Abu Karar and his men. "We have eyes all over Baghdad. We investigate the suspects and then we get them."

He describes how, a few days ago, he received a tip from a fellow Shia about a Sunni "terrorist group". "They were killing our Shia brothers, in Tobji ... The office in the area called on us to help. We went in a convoy of three cars. We stormed into the house. There was a small gun battle. We found three men; we arrested them."

Were the men questioned? "We don't need interrogations or trials, the informant had sworn by the Qur'an. We took them to the Seda and finished them there." The Seda is a small dirt berm on the edge of Sadr City, north-east of Baghdad, where bodies are often found....

Raid, a captain in the notorious Ministry of Interior commandos, confirms Abu Karar's claims. "When we arrest a suspect, sometimes we get a letter from a Moqtada office asking for the suspect to be transferred to their custody. We do it." He continues: "What can you do if you are policemen standing at a checkpoint and see militiamen with a dead body? Nothing. The policemen can't do anything. They are scared of the militia; they let them pass."