Looting has been a part of war at least since 333 B.C., when Alexander the Great strolled into the tent of King Darius III, helped himself to the vanquished Persian's best tapestries and commandeered the royal bathtub for a soothing victory soak. In the years since, victors have taken the spoils, and in their wake, ordinary citizens and opportunistic thieves have grabbed anything of value in that confused pause between war and peace.

All the looting at Baghdad's Iraq Museum had taken place by the time U.S. troops—engaged in toppling Saddam Hussein—arrived to protect it, on April 16, 2003. Between April 8, when the museum was vacated, and April 12, when the first of the staff returned, clubs in hand, thieves had plundered an estimated 15,000 items, many of them choice antiquities: ritual vessels, heads from sculptures, amulets, Assyrian ivories and more than 5,000 cylinder seals.

The looting proved less extensive than the early reports of 170,000 stolen artifacts, but the losses were nonetheless staggering. "Every single item that was lost is a great loss for humanity," says Donny George Youkhanna, the former director general of Iraqi museums, now a visiting professor at the State University of New York at Stony Brook. "It is the only museum in the world where you can trace the earliest development of human culture—technology, agriculture, art, language and writing—in just one place."

Before the war, leading archaeologists had warned that the museum was vulnerable, but neither Iraqi officials nor invading troops were prepared for such aggressive plunder. There was nothing like the World War II-era Monuments, Fine Arts, and Archives task force poised to secure, track down and recover Iraq's venerable treasures. But there was the "Pit Bull," also known as Marine Col. Matthew Bogdanos, a reservist, classics scholar and amateur boxer, who had earned his civilian nickname as a homicide prosecutor in New York City.

"I felt exactly the way the rest of the world did—outraged—when I heard of the looting in Baghdad," says Bogdanos, who was leading a counterterrorist unit in southern Iraq when he learned of the pillaging. He quickly got permission from the U.S. Central Command to form an ad hoc "Monuments" team, composed of 14 members with investigative experience. Bogdanos and his team dashed north to Baghdad, arriving April 20. They established security at the museum complex and, huddling with museum authorities, began an inventory of missing treasures. They dispatched descriptions to border guards, customs agents, international police agencies and archaeologists around the world. They put out the word that no one returning stolen items would be prosecuted. "If you bring something back to the museum," Bogdanos was fond of saying, "the only question you will be asked is whether you would like a cup of tea."

Over the next few weeks, stolen goods began to trickle back, including a 6000 B.C. pot wrapped in a 21st-century garbage bag and the Sacred Vase of Warka (c. 3200 B.C.), in the trunk of a car. Objects were unearthed from backyards, fished out of a cesspool, recovered in pre-dawn raids. Some simply reappeared on museum shelves. Other treasures were seized from international antiquities markets in Jordan, Lebanon, Syria, Kuwait, Saudi Arabia and New York. A scholar returning from the war zone was collared at John F. Kennedy International Airport and convicted of smuggling three 4,000-year-old cylinder seals from the museum's collection.

"Mothers turned in items stolen by their sons," says Bogdanos. "Sons turned in items stolen by their friends. Employees turned in items stolen by their bosses." And as the investigation unfolded, it developed that hundreds of the most valuable items missing from the museum—including a cache of gold jewelry from Nimrud—had not been stolen at all but stashed, since the Gulf War of 1990-91, for safekeeping in Iraq's Central Bank.

George estimates that about half of the 15,000 looted treasures have either been returned or secured in other countries until they can be safely repatriated. Still missing are thousands of cylinder seals, a famous eighth-century B.C. gold-and-ivory plaque known as The Lioness Attacking a Nubian and choice pieces of statuary from the ancient city of Hatra. An optimist with an archaeologist's long view of history, George believes that in the fullness of time, all of the antiquities will be returned. Meanwhile, many of Iraq's 12,500 archaeological sites continue to be vulnerable to looting, and the Iraq Museum remains closed, its treasures bricked up within interior storage rooms. "The museum must be the last place to be opened after everything else is completely secured in the country," says George.

After two tours in Iraq and service in the Horn of Africa and at the Pentagon, Bogdanos returned home to New York City in 2005, in time for the publication of his book, Thieves of Baghdad. (All royalties are being donated to the Iraq Museum.) He continues to investigate the Iraqi thefts as chief of a newly created antiquities task force in the New York County district attorney's office. "Until every last piece stolen from the Iraqi Museum has been recovered and returned to the Iraqi people," he says, "I will continue to be haunted by what is still missing."