DONNA GUERIN, a former partner in the defunct law firm Jenkens and Gilchrist, has pleaded guilty in what the trial judge has called the biggest US tax-fraud prosecution in history.

Guerin was initially convicted by a jury in May 2011 with three other defendants of running a 10-year tax shelter scheme that created more than $1 billion in phony losses. Three of the convictions, including Guerin’s, were overturned in June after US District Judge William Pauley found that a juror in the case lied about her past, including that she was an alcoholic and a suspended attorney.

Guerin, 52, pleaded guilty yesterday in Manhattan federal court to one count of conspiracy and one count of tax evasion. Her plea comes as prosecutors are preparing to retry the defendants whose convictions were overturned based on the misconduct of the juror, Catherine Conrad.

“I came to believe that many clients engaged in the transactions solely because they wanted to eliminate or reduce tax liability,” she said in court.

She faces a maximum of 10 years in prison on both counts, the judge said during the hearing. Sentencing is scheduled for January 11th. She has agreed to pay $1.6 million (€1.2m) in penalties. Her defence lawyer, Mark Rotert, declined to comment after the proceeding.

Guerin said she worked on tax shelters with Paul Daugerdas, also a defendant in the case, while the two were lawyers at former Chicago-based firm Altheimer and Gray. The two joined Dallas-based Jenkens and Gilchrist in 1998, she said, and continued their work in helping clients shelter income.

Guerin admitted to helping advise clients on how to conduct complex transactions that allowed them to wipe out financial gains. Guerin said she also provided opinion letters to her clients helping them assert that the deals were legitimate.

Pauley threw out the convictions of Guerin, Daugerdas and Denis Field, the former chief executive officer at accounting firm BDO Seidman LLP after finding that Conrad had lied repeatedly about her background.