Many United States Supreme Court decisions have overturned criminal convictions for the reason that the government employed false evidence to obtain the conviction or failed to disclose relevant evidence important to the defense. In reversing federal or state judgments, the Court often has located direct proof of wrongdoing by the prosecutor. The notorious "bloody shorts" case is an example in point.' There, the state introduced as evidence a pair of men's "blood-stained" undershorts to achieve conviction of the accused. When the blood turned out to be red paint, the Supreme Court granted habeas corpus relief to the defendant because "[it was further established that counsel for the prosecution had known at the time of the trial that the shorts were stained with paint ...” The prosecution deliberately misrepresented the truth."

Judicial opinions in this area of the law have frequently emphasized the prosecutor's historic duty not to convict but rather to do justice. Violations of this duty by the state's prosecuting officer can create constitutional problems of verdict-rupturing magnitude: "It is as much his duty to refrain from improper methods calculated to produce a wrongful conviction as it is to use every legitimate means to bring about a just one." That deliberate evidence-suppressing conduct by the prosecutor voids a conviction is clear. But the problem becomes more difficult when the hiding of documents or witnesses is accomplished not by the prosecutor but by a lower-ranking minion of the state. What if a police officer discovers important evidence which is helpful to the defendant and fails to call it to the attention of either the prosecutor or the defense?