State v. Glissendorf
In State v. Glissendorf, 235 Ariz. 147,7, 329 P.3d 1049, 1052 (2014), the Arizona Supreme Court stated that giving a Willits instruction as "a consequence for even innocent loss or destruction is necessary both to deter such action and to ensure that defendants do not bear the burden of the state's actions." 235 Ariz. 147,13, 329 P.3d at 1053.
The court pointed out that "the Willits instruction takes into account the state's explanation of the destruction by permitting jurors to draw an adverse inference only if they 'find that any such explanation is inadequate.'" Id.
In Glissendorf, the court stated "the 'failure to preserve potentially useful' evidence is not a denial of due process unless 'a criminal defendant can show bad faith on the part of the police.'" 235 Ariz. 147,11, 329 P.3d at 1052-53.
"To show that evidence had a 'tendency to exonerate,' the defendant must do more than simply speculate about how the evidence might have been helpful." Id.9.
The defendant must "'demonstrate that the lost evidence would have been material and potentially useful to a defense theory supported by the evidence.'" State v. Glissendorf, 233 Ariz. 222,17, 311 P.3d 244, 251 (App. 2013).