How have the courts dealt with allegations that heroin seized by the police was destroyed in the context of criminal proceedings?

For preliminary hearing purposes, it was established in Backus that, at least with respect to one of their informants, the defendants had given him heroin that they said had been seized in connection with the arrests of other persons. (People v. Backus, supra, 23 Cal.3d at pp. 383-384, 152 Cal.Rptr. 710, 590 P.2d 837.) That gave rise to the discussion of former Health and Safety Code sections 11474 and 11474.5. The court held that those sections "mandate the disposition of controlled substances seized by peace officers" and that the defendants, individual police officers, "had no authority to otherwise dispose of any heroin seized from a person against whom charges related to possession of the heroin were contemplated or filed." (Id., at p. 384, 152 Cal.Rptr. 710, 590 P.2d 837.) The court [224 Cal.App.3d 1346] continued: "Nor could they claim to reasonably believe that any part of such seized evidence could be diverted to their investigatory activities. Due process requires that criminal defendants have an opportunity to examine, and in appropriate cases have chemical test performed on, evidence to be offered against them." (Ibid. Citation and footnote omitted.) It is clear that the court was concerned that evidence in a pending case was being used, and thereby destroyed.