New probe into US attorney affair
Alberto Gonzales resigned after being harshly criticised over the affair
The US attorney general has appointed a special prosecutor to look into the firing of nine US attorneys in 2006.
The move came as a report into the affair by the inspector general of the justice department criticised the actions of administration officials.
The report was critical of White House officials, lawmakers and the former Attorney General Alberto Gonzales.
The investigation was prompted by fears that the attorneys had been removed for political reasons.
Special Prosecutor Nora Dannehy will now investigate whether officials questioned during the probe lied to investigators in an attempt to obstruct justice.
"Serious allegations involving potential criminal conduct have not been fully investigated or resolved," Inspector General Glenn Fine said in his report.
The appointment of a special prosecutor with the power to force witnesses to testify was one of his key recommendations.
The row began when nine US attorneys were removed from their positions by the US Department of Justice in December 2006.
At the time, the department said that the attorneys had been fired for poor performance.
But it later emerged that the fired attorneys had not been rated any more poorly than many of their colleagues, leading many observers to conclude that the sackings had been politically-motivated.
Some of the attorneys had been involved in the prosecution of high-profile Republican members of Congress, while others had refused to investigate allegations of voter fraud against Democrats.
US attorneys investigate and prosecute court cases for the government.
They can be dismissed at any time, but may not be removed for political reasons.
The then head of the justice department, Attorney General Alberto Gonzales, came under fire for the sackings, and eventually resigned his position.
A number of other justice department officials also resigned.
The inspector general's report was highly critical of Mr Gonzales's role in the affair, saying he bore "primary responsibility" for the sackings, that he "abdicated" his leadership role and was "remarkably unengaged" in the process.
Other officials, including former senior Bush aide Karl Rove, were criticised for failing to co-operate with the investigation.