In a criminal case, it often appears that the deck is stacked in favor of the prosecution. After all, the prosecution tends to have greater access to evidence and witnesses than the defense. One of the ways our system tries to level the playing field is by requiring prosecutors to give defendants access to evidence that might help exonerate them. This type of evidence is often referred to as exculpatory evidence.
Recently, a former Alaska legislator's corruption conviction was overturned because the prosecution failed to give him access to exculpatory evidence.
Former Alaska Representative Victor Kohring was convicted in 2007 of accepting and soliciting bribes from executives working for VECO Corp., an oil services company. Kohring was one of 12 people charged in broad corruption investigation that also ensnared U.S. Senator Ted Stevens. The testimony of former VECO executive Bill Allen was instrumental in securing the convictions of Kohring and Senator Stevens.
However, Stevens' conviction was overturned and the indictment against him was dismissed after officials in the Obama administration determined that the prosecution had withheld important exculpatory evidence from the defense. Only after the government dropped the criminal charges against Stevens, did the government give Kohring's defense team access to thousands of pages of documents that would have helped Kohring's case. Some of the withheld evidence indicated that Bill Allen had significant memory problems and this could have been used to undermine Allen's damaging testimony.
Recently, the 9th Circuit Court of Appeals determined that the government wrongfully withheld evidence from Kohring. The court overturned Kohring's conviction and ordered that he be given a new trial.
Source: Westlaw News, "Appeals court overturns Alaska lawmaker's conviction," Yereth Rosen of and Andrea Evans, 3/11/2011