Prosecutors who tried Sen. Ted Stevens (R-Alaska) have asked the federal judge to ignore a key witness’s attempt to recant his testimony, arguing that the witness is only trying to protect his family members from prosecution.

Stevens was convicted Oct. 27 on seven counts of failing to disclose gifts on his annual financial disclosure forms. The central focus of the case was hundreds of thousands of dollars worth of renovations to his home that were provided by employees of VECO, an oil-services company owned by his friend Bill Allen.

One of the government’s key witnesses was VECO employee David Anderson, who testified about the extensive work that he did on the Stevens’ home renovation project while on VECO’s payroll.

In March, Anderson, apparently believing that Allen was planning to have him killed, signed an affidavit saying the government had promised complete immunity for him, his family and his friends in exchange for his testimony against Stevens.

During his trial testimony, Anderson admitted that the affidavit was false, saying there was no promise of immunity.

But in a Nov. 15 letter to the judge, Anderson wrote, “I testified to the fact that there was never immunity for me or my family and friends. That simply is not true.” Anderson wrote that he testified that the affidavit was false only because he thought it would ensure that it would end his involvement in the case. If he had not believed there was an immunity deal, he said, “I would never have testified, I would have pleaded the fifth.”

Stevens’ attorneys asked Judge Emmet Sullivan to call a hearing to investigate Anderson’s new claims, suggesting that the alleged misconduct was serious enough to warrant a dismissal of the charges against Stevens or a new trial.

But the Justice Department, in a motion filed late Monday, said the judge should not call a hearing on Anderson’s claims.

Anderson’s original affidavit and the Nov. 15 letter were attempts to protect a family member who is a suspect in Alaska’s broader political corruption scandal, the government alleges. While the government names this person only as “Family Member A,” the Anchorage Daily News said the person is former state Senator Jerry Ward, who has a close personal relationship with Anderson.

According to the Justice Department, Anderson has tried to broker several conversations between the FBI and Family Member A, but has never claimed during his contacts with the FBI that Family Member A has immunity because of Anderson’s cooperation in Stevens’ trial. In addition, the government claims that it has reviewed security tapes of the FedEx Kinkos shop from which Anderson’s Nov. 15 letter was sent, which reveal that it was the family member, not Anderson, who actually sent the letter to the government in which Anderson recanted his testimony.

“Anderson’s claims of immunity — whether in the form of the [original] March affidavit or in the November 15 letter — are patently false,” prosecutors allege. In addition, the issue of the immunity deal has nothing to do with the charges against Stevens, the government argues, so there is no purpose to holding a hearing on Anderson’s latest claims.