California v. Trombetta - 467 U.S. 479, 104 S. Ct. 2528 (1984)

Rule:

Whatever duty the United States Constitution imposes on the states to preserve evidence, that duty must be 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 is 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.

Facts:

Defendants submitted to Intoxilyzer tests upon being stopped for drunken driving. After registering blood-alcohol concentrations substantially higher than 0.10 percent, defendants were charged with driving while intoxicated in violation of Cal. Veh. Code § 23102 (1981). Defendants moved to suppress the test results on the ground that the arresting officers failed to preserve the samples of defendants' breath. Such motions were denied. Upon consolidation, the state appellate court concluded that due process required law enforcement agencies to establish rigorous procedures to preserve the captured evidence or its equivalent for the use of defendants. After the state supreme court denied certiorari, the State sought further review.

Issue:

Did the Due Process Clause of the Fourteenth Amendment require law enforcement agencies to preserve breath samples of suspected drunk drivers in order for the results of breath-analysis tests to be admissible in criminal prosecutions? 

Answer:

No.

Conclusion:

The Court reversed the appellate court’s decision, holding that the due process clause of the U.S. Const. amend. XIV did not require the State to preserve breath samples in order to introduce the results of breath-analysis tests at trial. Even if it was assumed that the Intoxilyzer results were inaccurate and that the breath samples might, therefore, have been exculpatory, it did not follow that defendants were without alternative means of demonstrating their innocence.