But the recent departure of two investigators from that commission has aroused concerns among some U.S. Congressmen about the panel's work. One of the investigators, Robert Parton, resigned last month -- reportedly because he believed it was too soft on UN Secretary-General Kofi Annan.
Last week, Parton turned over documents from the Volcker commission to the International Relations Committee of the U.S. House of Representatives. Volcker believes Parton violated a confidentiality agreement and is in talks with various Congressional officials on how to reconcile their parallel investigations.
U.S. Senator Norm Coleman heads one of four Congressional panels examining oil-for-food program abuses. He has been critical of UN cooperation with the Congress. His spokesman, Tom Steward, told RFE/RL the latest developments raise further doubts: "The questions surrounding [Parton's] departure have certainly raised more questions and concerns on the part of Senator Coleman about the credibility of Mr. Volcker's entire investigation."
Coleman, who has called for Annan's resignation, is expected to release a report tomorrow detailing how former Iraqi President Saddam Hussein bought influence from UN member states and officials under the program. He will chair a hearing on his latest findings on 17 May.
Volcker's inquiry has so far determined that the head of the UN program, Benon Sevan, improperly interfered with oil contracts. It has raised concerns about the business dealings of Annan's son, Kojo, who worked for a company contracted to monitor goods shipments.
In March, the Volcker commission found no evidence that the company, Cotecna, was subject to any improper influence by Kofi Annan during the bidding process. But the commission criticized the UN secretary-general for failing to thoroughly investigate charges of conflict of interest when they arose and it cited several top aides for questionable behavior.
A spokesman for the commission, Michael Holtzman, tells RFE/RL the panel's work has been fair and independent. He says it is trying to cooperate with U.S. Congressional investigators.
"We have followed the facts wherever they may go," Holtzman said. "Our second interim report was not soft at all on the secretary-general and it was incredibly severe, I think, on the secretary-general in terms of the way he administers the program, the way he executed an internal investigation regarding his son and Cotecna's involvement in the bidding process. This was not an exoneration by any stretch."
Still, the dispute over Parton's departure from the commission has led to an unusual power struggle between the Congress of the UN's largest member and a UN-appointed investigative commission.
The administration of George W. Bush has repeatedly backed the Volcker commission and has expressed its support of Annan as an agent for UN reform. But it has had to acknowledge the role of the U.S. Congressional inquiries, as State Department spokesman Tom Casey did yesterday: "We support the work of the Independent Inquiry Committee, the Volcker committee, in its work. But we also believe it's important for the U.S. Congress to be able to have a look at this issue and make sure that it is comfortable with the facts and that it understands what happened. It's an important issue for the American people to know about."
Defenders of the UN have charged that the Congressional committees appear to be motivated, in part, by lingering outrage over UN opposition to the U.S.-led war to oust Hussein. Others have testified in Congress that the vast majority of the estimated $10 billion Hussein siphoned during the time of the program came through smuggling and other channels controlled by UN Security Council members.
William Luers is president of the United Nations Association, a New York-based policy institute that promotes U.S. involvement in the United Nations. He tells RFE/RL that little is understood about the relationship that existed during the Iraqi sanctions regime between the UN Secretariat, run by Annan, and the Security Council.
"There's really a lot of blame to go around here and most of Congress has been focused on -- in often a not very rational way -- focused on the UN role, whereas the UN also includes, as you've overheard over and over again, the member states who were most directly involved."
The Volcker commission's final report is due to focus on the role of Security Council and other member states in contributing to abuses of the Iraqi humanitarian program. That report is due out this summer.