The Justice Department filed court papers this morning asking a federal judge to toss out the conviction of former  Sen. Ted Stevens (R-Alaska) on corruption charges.

The move comes as a federal judge was preparing to conduct hearings to probe allegations of prosecutorial misconduct by the team that tried one of the most powerful Republicans in Congress. Stevens, 85, was convicted in October on seven counts of making false statements on financial disclosure forms to hide about $250,000 in gifts and free renovations to his Alaska home. Stevens's attorneys have urged U.S. District Judge Emmet Sullivan to drop the case and prevent prosecutors from seeking to retry the former senator, who lost a reelection bid about a week after his guilty verdict.

They have argued that prosecutors with the Justice Department's Public Integrity unit withheld key pieces of evidence and mishandled witnesses.

During the trial, Sullivan chastised prosecutors several times for such errors.

More recently, the Justice Department was forced to disclose a memo written by an FBI agent who complained of the same things. Sullivan recently held several prosecutors in contempt for failing to comply with a court order. Six members of that prosecution team then withdrew from the case in matters dealing with allegations of misconduct.