Salem Chalabi's position as the head of the tribunal that will try Saddam Hussein and other former Iraqi officials has been thrown into doubt by a charge of involvement in murder.
A US-educated lawyer, he was at the heart of framing parts of Iraq's new constitution and was appointed head of the war crimes tribunal responsible for bring Saddam Hussein to justice.
Salem Chalabi say he can prove he is innocent of the charges
But now, if convicted of involvement in murder, a charge he denounces as "ridiculous", he could face the death penalty newly reintroduced into the Iraqi law he helped to shape.
Mr Chalabi was born in Baghdad 41 years ago. His uncle Ahmed Chalabi - later to become one of the most famous overseas opponents to Saddam Hussein and at one time a favourite among some US officials to become the new Iraqi president - had already left to live in the US and UK.
Salem Chalabi ended up following a similar route. He went to some of the US' top universities - Columbia, Northwestern and Yale - where he obtained degrees in international relations and law, and later worked for a leading London-based firm of solicitors, Clifford Chance.
And he stayed close to his uncle, who later became one of the most prominent figures of the Iraqi National Congress, a US-backed coalition of Iraqi exile groups also based in the British capital.
He is reported to have worked on various law-related projects, including helping to draw up suggestions for a possible post-Saddam constitution before the war was waged.
After Saddam Hussein's fall Mr Chalabi - like his uncle - returned to Baghdad and was soon playing key roles in the country's reconstruction.
He was on the panel that drafted the Basic Transitional Law, Iraq's interim constitution, and was then named head of the war crimes tribunal.
His power and influence attracted opposition - from some who did not want those who had been abroad during the Saddam years to have so much responsibility and others who thought him too close to the Bush administration in Washington.
His uncle had been a favourite of the Pentagon and Salem Chalabi also had ties to US politicians such as Douglas Feith, undersecretary of defence, whose former law partner Marc Zell worked with Mr Chalabi in launching an international legal firm in Baghdad.
Mr Chalabi appeared fully aware of the opposition and even dangers facing him, telling the BBC in June that there were threats against "everybody involved in trying to build a democratic Iraq".
Salem's uncle Ahmed has also been subject to damaging allegations
His uncle fell dramatically from grace with the US. It was alleged that he spied for Iran. He also suffered the indignity of being roused from his bed while Iraqi police and US soldiers raided his home and offices, but Salem Chalabi's position was still not in doubt.
Saddam Hussein's appearance in handcuffs before a court under the auspices of his tribunal must surely have been a career highlight for Mr Chalabi.
But just two months later came the arrest warrant that could see him jailed or even executed.
He told the BBC that he was confident he could prove his innocence in any involvement in the murder of Haithem Fadhil, director-general of the Iraqi finance ministry.
But he said his opponents might find other ways to remove him from influence.
"My life is daily threatened in Baghdad because of what I am doing."