State v. Horcasitas, 1 CA-CR 23-0215

Gabriel Horcasitas was tried for several serious felonies after a road rage incident in which he shot and killed another driver in Chandler, Arizona.
The State charged Horcasitas with first- and second-degree murder, drive-by shooting, and multiple counts of endangerment; he asserted self-defense and related defenses.
During trial, it was revealed that police had performed a Cellebrite analysis (forensic data extraction) on the victim's phone, but the results had not been properly disclosed to the defense until well into the trial.
The late-disclosed phone data included text messages suggesting the victim had a history of aggressive driving and a tendency to "snap"—evidence relevant to Horcasitas’s self-defense argument.
The trial judge found the disclosure came too late for effective use by the defense and granted a new trial, finding the State violated its disclosure obligations under both Brady v. Maryland and Arizona Rule 15.1.
The State appealed the order granting a new trial; the appellate court upheld the trial court's ruling.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Did the State violate disclosure obligations under Brady and Rule 15.1 by not timely disclosing the Cellebrite records?	The State met its obligations; the defense had notice of the records and there was no relevant, exculpatory material.	The records had exculpatory information, were not timely disclosed, and could have aided in the defense.	Yes, the State's disclosure was untimely and incomplete, violating its obligations.
Was disclosure during trial sufficient to cure any violation?	Disclosure was made during trial, so no prejudice occurred.	Disclosure came too late for effective use; expert analysis could not be secured in time.	Disclosure was too late to be of value to the accused and did not cure the violation.
Did mentioning the existence of forensic data in a police report suffice for disclosure?	Yes; reference in reports provided adequate notice to the defense.	No; actual contents (texts) and exculpatory material were unknown to the defense.	No; notice of existence is insufficient without actual disclosure and knowledge of exculpatory content.
Were the texts on the victim’s phone material enough to require disclosure under Rule 15.1(b)(8)?	The texts were neither material nor exculpatory.	The texts supported the self-defense and mitigation case.	Yes; the texts could mitigate guilt and punishment and should have been disclosed.

Brady v. Maryland, 373 U.S. 83 (1963) (prosecution must disclose evidence favorable to defendant that is material to guilt or punishment)
State v. Jessen, 130 Ariz. 1 (Ariz. 1981) (Rule 15.1 disclosure obligations are broader than Brady)
State v. Jones, 120 Ariz. 556 (Ariz. 1978) (prosecution must fully disclose exculpatory evidence unless the defense already knows)
United States v. Gordon, 844 F.2d 1397 (9th Cir. 1988) (Brady disclosure must be timely to be useful to the defense)