Federal auditors suggested Monday that $6.6 billion in cash that went missing in May 2004 in Iraq was stolen. The conclusion comes after years of investigations by the Defense Department. The missing money is not only an embarrassment to the Pentagon, but also a bone of content between Washington and Bagdad, as Iraqi officials are threatening to sue for money since it came from Iraqi oil sales, seized Iraqi assets and surplus funds from the UN’s oil-for-food program. U.S. officials began sending planeloads of cash shortly after the U.S.-led invasion in 2003, and in May 2004, 20 planeloads carrying some $12 billion in shrink-wrapped bills—the believed to be the largest cash airlift of all time—left for Iraq. U.S. officials didn’t keep strict financial controls, although Pentagon officials have maintained until now they could have tracked down the money if they had enough time to track down the records.