US Marine Cpl John Hoellworth stopped me at the entry to the Amn al-Amn, the main state security building in Baghdad.
The ugly compound of more than a dozen high-rise brown buildings was so feared by Iraqis that many would not even drive past it. A few years ago, I interviewed Dr Hussain al-Shahristani, a scientist who was imprisoned and tortured by Saddam Hussein's regime because he refused to co-operate in the nuclear weapons programme. Dr al-Shahristani described how he was hung by his wrists, beaten and given electrical shocks in the Amn al-Amn's underground prison.
But Cpl Hoellworth was adamant. "We can only let journalists in who've been through the CFLCC process," he said, pronouncing the acronym "cif-lick"; it means journalists who applied for Pentagon accreditation in Kuwait City. "There's a contract between them and us," he explained.
While we talked, Iraqi cars pulled up to the building several times, to be met by marines running out, stopping on one knee and taking aim at them, shouting to the motorists to go away. "This building cast a shadow of evil over all of Baghdad," Cpl Hoellworth said. "Now that the regime is toppled, they just want to come and look at it." The marines had found no torture chambers yet, he said, only tunnels, and miles of archives.
As I reached my taxi, an Iraqi car pulled up alongside us. Two men got out. "Did the Americans find any prisoners in the Amn al-Amn building?" one asked pleadingly. "My father and his brother have been missing for 20 years - we think they might be in there." This weekend, the US Defence Secretary, Mr Donald Rumsfeld, rejected criticism of anarchy in the newly "liberated" Iraqi capital, blaming it on "sensationalism" by the press. The marines nonetheless summoned several high-ranking Iraqi police officers to the Palestine Hotel for consultations, and began interviewing former policemen in the hope they could be instantly rehabilitated and put back on the streets, to stop the looting that continued yesterday. There is still no sign of Iraqi police, but the marines began deploying their forces more widely, stationing some in hospitals and schools, and carrying out a few patrols in the streets of Baghdad.
Aside from Saddam Hussein's main presidential complex and the al-Rashid Hotel, only three government buildings were occupied and protected from the outset by US forces: the Amn al-Amn and its sister bureaucracy in repression, the Interior Ministry; and the Oil Ministry. The security buildings are of obvious interest for what they may reveal about Saddam's evil deeds and internal opposition. And the Oil Ministry may still hold records about oil facilities and exploration, of immense interest to the US oil lobby that encouraged President George W. Bush to invade this country.
Although the US administration said it wanted to preserve the government apparatus intact for postwar reconstruction, none of the ministries that might have been useful to ordinary Iraqis - Irrigation, Education, Industry, Trade, Transportation, Foreign Affairs, Culture, to name a few - survived the weekend's frenzy of continued looting and arson.
The angry Shias turned on Iraq's heritage too, looting archaeological museums in Baghdad and Mosul. At the Iraq Museum, vandals smashed pots, shards and statues, all painstakingly numbered and labelled, on the floor. Some were thousands of years old. The Iraqi Olympic Committee, which was the headquarters of Saddam's hated eldest son Uday, was more thoroughly burned than any other. It was the only Olympic Committee in the world to have a prison in its basement. The mob torched it so thoroughly that the city block-sized building looked as if it had melted.
Despite the change in US military policy - for the first three days US officers said they were here only to destroy the regime, not to act as policemen - the anarchy continues. Several ministries appeared to have been reignited yesterday, after the giant bonfires of Friday night, and I saw men taking furniture out of the Planning Ministry even as it burned. The building was attacked by A-10 "wart-hogs", which fire depleted uranium shells, so the looters may pay for their thieving with cancer. The Melia Mansour Hotel, where I stayed for three nights just before the war started, was also on fire.
At the Foreign Ministry, I was greeted by a looter in a stained galabiyah who wore a gas mask and wanted to shake my hand. One well-dressed looter carried an armful of documents pertaining to Iraqi-German relations; I suspect he worked for the German embassy and had been asked to retrieve the papers.
The chandelier and vaulted ceiling of the Foreign Ministry foyer were charred, and I could feel the heat of the fire still burning higher up in the building. In the absence of electricity, looters worked by the light of kerosene lanterns. In central Baghdad, people pushed trolleys loaded down with booty, a tractor pulled stolen goods on a wagon, and a horse pulled another.
So I was astonished to see two marines stopping looters at gunpoint in Andalos Square. For two hours, they told me, Cpl Samson Krueger and Lance Cpl Travis Bennett had hailed vehicles driving by with what looked like stolen property.
They'd amassed a pitiful little pile on the pavement: two sinks, a bidet, a television, a desk and an air conditioner. "If they have weapons, we have instructions to detain them and take them to our post," Cpl Krueger said. They hadn't arrested anyone - hardly an aggressive attempt to disarm Baghdad, in view of the amount of gunfire one hears in the streets.
But the clincher was what I saw a few minutes later, at the marines' main stronghold outside the Palestine Hotel. Two freight lorries, one half-filled with a fancy bedroom set, the other a shipment for the French group Médecins Sans Frontières, drove right through the knot of vehicles and people being checked by marines. The young men riding on the back of the MSF truck looked like looters to me, but the marines waved them on.