Police Failure to Preserve Evidence - Due Process Violation: In California v. Trombetta (1984) 467 U.S. 479, law enforcement failed to preserve the defendant's breath samples used to determine blood-alcohol level in prosecutions for driving under the influence of alcohol. The court found California's policy of not preserving breath samples does not violate a defendant's due process rights. The duty to preserve evidence is "limited to evidence that might be expected to play a significant role in the suspect's defense. To meet this standard of constitutional materiality, , evidence must both possess an exculpatory value that was apparent before the evidence was destroyed, and be of such a nature that the defendant would be unable to obtain comparable evidence by other reasonably available means." This standard was not met where the "chances were extremely low that the samples would have been exculpatory" and the defense could still attack the reliability of the breath tests. (Id. at pp. 488-489 at p. 422-423, fn. omitted.) In Arizona v. Youngblood (1988) 488 U.S. 51, the state court reversed the defendant's convictions for child molestation, sexual assault, and kidnapping, because state officials failed to preserve semen samples from the victim's body and clothing. Defendant raised a mistaken identity defense. Reversing the state court's decision, the high court held "that unless a criminal defendant can show bad faith on the part of the police, failure to preserve potentially useful evidence does not constitute a denial of due process of law." (Id. at p. 58 at p. 289.) The court in Youngblood reasoned that "the Due Process Clause of the Fourteenth Amendment, as interpreted in Brady v. Maryland (1963) 373 U.S. 83 makes the good or bad faith of the State irrelevant when the State fails to disclose to the defendant material exculpatory evidence. But we think the Due Process Clause requires a different result when we deal with the failure of the State to preserve evidentiary material of which no more can be said than that it could have been subjected to tests, the results of which might have exonerated the defendant. Part of the reason for the difference in treatment is found in the observation made by the Court in Trombetta, supra, 467 U.S. at page 486, that 'whenever potentially exculpatory evidence is permanently lost, courts face the treacherous task of divining the import of materials whose contents are unknown and, very often, disputed.' Part of it stems from our unwillingness to read the 'fundamental fairness' requirement of the Due Process Clause, , as imposing on the police an undifferentiated and absolute duty to retain and to preserve all material that might be of conceivable evidentiary significance in a particular prosecution. We think that requiring a defendant to show bad faith on the part of the police both limits the extent of the police's obligation to preserve evidence to reasonable bounds and confines it to that class of cases where the interests of justice most clearly require it, i.e., those cases in which the police themselves by their conduct indicate that the evidence could form a basis for exonerating the defendant." (488 U.S. at pp. 57-58 at p. 289.) Thus, a due process violation occurs when law enforcement officials fail to preserve evidence that is exculpatory, the exculpatory value was apparent before the evidence was destroyed, and was of such a nature that the defendant would be unable to obtain comparable evidence by other means. (Trombetta, supra, 467 U.S. at p. 489 81 L. Ed. 2d at p. 422.)