State of Iowa v. Cody Austin MacKenzie, 14-1523

Defendant Cody Mackenzie convicted by jury for possession of marijuana after police searched his bedroom and seized a small amount of plant material.
Detective Joe Caffery located the suspected marijuana, placed it in a clear plastic container, sealed that container in a heat-sealed plastic bag with evidence tape, and initialed the bag.
Caffery delivered the item (Exhibit 232) to the evidence vault custodian, Detective Brian Staszewski, who logged it into the electronic evidence system and later opened and tested the substance.
Staszewski testified the bag bore his initials and the date of testing, he recognized the exhibit’s appearance, and he had no doubt it was marijuana.
The trial court initially sustained the defense chain-of-custody objection but later admitted the exhibit after testimony; the court found the testimony and the exhibit’s appearance sufficient to make tampering or substitution improbable.
Mackenzie appealed, arguing the State failed to prove the requisite chain of custody; the appellate court affirmed.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether the State established an adequate chain of custody for Exhibit 232	State: Testimony and evidence-room procedures make tampering or substitution improbable	Mackenzie: Foundation insufficient; chain of custody not proven	Court: Foundation adequate; admission discretionary and not abused

State v. Mehner, 480 N.W.2d 872 (Iowa 1992) (State must show it is reasonably probable tampering or substitution did not occur)
State v. Bakker, 262 N.W.2d 538 (Iowa 1978) (admission over chain-of-custody objection reviewed for abuse of discretion)
State v. Biddle, 652 N.W.2d 191 (Iowa 2002) (prosecution need only show circumstances making tampering or substitution improbable)
State v. Piper, 663 N.W.2d 894 (Iowa 2003) (continuous custody showing renders tampering improbable; doubts go to weight)
State v. Hanes, 790 N.W.2d 545 (Iowa 2010) (overruled Piper on other grounds)