State of Minnesota v. Heather Leann Horst, 880 N.W.2d 24

Background

Heather Horst was convicted of first-degree premeditated murder for soliciting and aiding Aaron Allen to kill her husband; jury found she planned, purchased supplies, handed Allen a gun, and coordinated post-shooting events.
After the killing Horst and a friend (A.P.) were interviewed at the police station; Horst was not given Miranda warnings, and police later seized her cellphone during the interview without a warrant.
Police obtained search warrants for Horst’s medical records from multiple providers spanning eight years to investigate her miscarriage claims; the State agreed not to introduce those records at trial.
Key trial testimony included cooperating witness Allen (who pleaded guilty and received a 40‑year term in exchange for cooperation), corroborating texts, store receipts, video footage, and purchase records.
Horst raised multiple appellate challenges: suppression of interview statements (Miranda), suppression of cellphone evidence (Fourth Amendment/exigency), validity/scope of medical‑records warrants, failure to give accomplice‑corroboration jury instruction, sufficiency of the evidence, and denial of a juror‑for‑cause challenge.

Issues

Issue	Plaintiff's Argument (Horst)	Defendant's Argument (State)	Held
Whether statements from station interview were subject to Miranda suppression	Interview was custodial; Miranda warnings required and omission made statements inadmissible	Interview was non‑custodial (voluntary trip, unlocked room, personal effects, free to leave)	Non‑custodial; statements admissible
Whether warrantless seizure of Horst's cellphone violated Fourth Amendment	Seizure required warrant; no exigency because electronic warrants were available and officer had breaks to seek one	Exigent circumstances existed (probable cause + risk evidence could be destroyed; limited temporary seizure)	Exigency justified brief warrantless seizure; denial of suppression affirmed
Whether search warrants for medical records were overbroad and required suppression or reversal	Warrants lacked particularity/temporal limits; State's access to privileged records prejudiced Horst requiring suppression or new trial	Records were not used at trial; exclusionary rule remedy inapplicable where no tainted evidence was admitted	Even if warrants defective, any error harmless beyond a reasonable doubt because records not admitted and evidence of guilt overwhelming
Whether court's failure to give accomplice‑corroboration instruction was reversible error	Sua sponte instruction required; omission impaired rights because key testimony came from accomplices	Jury had corroborating evidence, jury informed of deals/credibility; any error was harmless	Plain error standard not met; omission did not affect substantial rights
Sufficiency of the evidence for first‑degree premeditated murder under accomplice‑liability theory	Insufficient corroboration; circumstantial‑evidence standard should apply	Direct evidence (statements, acts, purchases, texts) proved mens rea and actus reus; traditional standard controls	Evidence sufficient; conviction affirmed
Whether denial of removing a juror for cause was an abuse of discretion	Juror’s prior acquaintance with investigator compromised impartiality	Relationship was remote and juror repeatedly affirmed impartiality; trial court best positioned to assess demeanor	No abuse of discretion; denial affirmed

Key Cases Cited

Miranda v. Arizona, 384 U.S. 436 (1966) (Miranda warnings required for custodial interrogation)
Katz v. United States, 389 U.S. 347 (1967) (Fourth Amendment protects reasonable expectations of privacy)
Place v. United States, 462 U.S. 696 (1983) (temporary seizure of property permissible pending warrant when exigent circumstances exist)
Illinois v. McArthur, 531 U.S. 326 (2001) (temporary seizure/restriction to preserve evidence justified by exigency)
Missouri v. McNeely, 569 U.S. 141 (2013) (exigency analysis requires case‑by‑case inquiry; warrants preferred when reasonably practicable)
Riley v. California, 573 U.S. 373 (2014) (cellphones contain large amounts of personal data; seizure to prevent destruction can be sensible)
Mapp v. Ohio, 367 U.S. 643 (1961) (exclusionary rule as remedy for illegal searches/seizures)
Wong Sun v. United States, 371 U.S. 471 (1963) (fruits doctrine limits admissible evidence derived from illegal searches)
Leon v. United States, 468 U.S. 897 (1984) (exclusionary rule has limits; good‑faith exceptions and evidentiary scope)
State v. Vue, 797 N.W.2d 5 (Minn. 2011) (custody‑indicia test and totality‑of‑circumstances for Miranda analysis)
State v. Sterling, 834 N.W.2d 162 (Minn. 2013) (mixed question of law and fact for custodial determination; appellate review standard)
State v. Thompson, 788 N.W.2d 485 (Minn. 2010) (station interview can be non‑custodial under certain circumstances)
State v. Flowers, 788 N.W.2d 120 (Minn. 2010) (sufficiency review where State proved elements by direct evidence)