*Judge voids case, orders probe of prosecutors

*Ruling comes at delicate moment for Justice Department

*Stevens says his "faith restored" in justice system (Adds Justice Dept. comment, background)

By Randall Mikkelsen

WASHINGTON, April 7 (Reuters) - A U.S. judge threw out a corruption verdict against former Republican Senator Ted Stevens on Tuesday and ordered a criminal probe into "shocking" Justice Department misconduct, in a blow to a legal system marred by accusations of Bush administration abuses.

U.S. District Judge Emmet Sullivan said prosecutors deliberately withheld exculpatory evidence from the defense in the Stevens case, despite repeated instructions and three civil contempt citations.

Prosecutors have a duty to disclose such evidence whether their cases involve "a public official, a private citizen or a Guantanamo Bay detainee," Sullivan said.

The ruling is another stain on the Justice Department which was riven with accusations that it had become overly politicized under former President George W. Bush and that it violated people's rights and bungled high-profile cases.

It came as Attorney General Eric Holder seeks to restore the department's reputation and reverse legal policies formulated during the Bush administration.