Does the failure to preserve evidence in a criminal case constitute a due process violation?

Although the state's good or bad faith in failing to preserve evidence is ordinarily irrelevant to assessing whether its conduct amounted to a due process violation (Arizona v. Youngblood (1988) 488 U.S. 51, 57 (Youngblood)), it is of great significance when the challenge to the state's conduct is based on the failure to preserve potentially exculpatory evidencethat is, "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." (Ibid.) In such a case, "'"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

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