What is the current state's duty to preserve evidence in the context of a criminal case?

"[T]he suppression by the prosecution of evidence favorable to an accused upon request violates due process where the evidence is material either to guilt or to punishment, irrespective of the good faith or bad faith of the prosecution." (Brady v. Maryland (1963) 373 U.S. 83, 87.) "Trombetta outlines how the state's failure to preserve evidence may violate those rights. In Trombetta, the high court limited the state's affirmative duty to preserve evidence to that which 'might be expected to play a significant role in the suspect's defense.' [Citation.] This standard of 'constitutional materiality' imposes two requirements that a defendant must meet in order to show a due

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process violation. As an initial matter, the evidence must 'possess an exculpatory value that was apparent before [it] was destroyed.' [Citation.] Additionally, it must 'be of such a nature that the defendant would be unable to obtain comparable evidence by other reasonably available means.'" (People v. Lucas (2014) 60 Cal.4th 153, 221, disapproved on other grounds in People v. Romero (2015) 62 Cal.4th 1.)

In Arizona v. Youngblood (1988) 488 U.S. 51, the court found that "[U]nless 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, italics added.)