State v. Millis, 391 P.3d 1225

Jeremy Millis babysat his ex-girlfriend S.F.’s eight-month-old son C.K. on Jan 24, 2013; the child was healthy earlier that day.
That night and the next morning C.K. became nonresponsive; medical imaging showed bilateral subdural hematomas, extensive retinal hemorrhages, bruising, and hypoxic ischemic injury; doctors concluded injuries were non-accidental.
Millis texted S.F. about the child’s earlier coughing; later admitted to detectives and on recorded calls that he had squeezed/choked C.K., and gave inconsistent accounts about a head impact.
C.K. died five days after hospital admission; the pathologist ruled the death a homicide from blunt-force head trauma and hypoxic ischemic injury.
Millis was tried by jury, convicted of intentional or knowing child abuse (circumstances likely to result in death or serious physical injury) and first-degree murder (felony murder), and sentenced to life with parole ineligibility plus a consecutive term.
On appeal Millis argued (1) erroneous preclusion of expert testimony diagnosing him with autism spectrum disorder (ASD), (2) duplicitous charges / lack of unanimity, and (3) prejudice from the victim’s use of a facility dog in the courtroom.

Issue	Millis’ Argument	State’s Argument	Held
Preclusion of ASD expert testimony	Proffered testimony would show character/observation evidence (difficulty interacting) and reduce likelihood he formed intent; not offered to negate mens rea	Testimony was diminished-capacity evidence offered to negate intent and thus inadmissible under Arizona law	Court affirmed exclusion: testimony was impermissible diminished-capacity evidence; no abuse of discretion or reversible error
Duplicitous charge / jury unanimity	Jury could have convicted on different causal theories (blunt-force head trauma v. choking) making verdict non-unanimous	First-degree murder and §13-3623(A) child abuse are single unified offenses; unanimity as to precise means not required; state had substantial evidence for each means	Court held no duplicity error and unanimity not required as to means; no fundamental prejudice shown
Victim accompanied by facility dog at trial	Presence of dog was prejudicial, invited sympathy, denied Millis a fair trial	Trial court exercised discretion; dog sat in gallery not at witness stand; other jurisdictions permit facility dogs; Arizona later enacted statute permitting such accommodations	Court found no abuse of discretion or reversible due-process error; harmless if any error

State v. Mott, 187 Ariz. 536 (affirming exclusion of psychiatric evidence offered to negate mens rea; rejecting diminished-capacity defense)
Clark v. Arizona, 548 U.S. 735 (distinguishing admissible observation evidence from impermissible mental-disease evidence)
Schad v. Arizona, 501 U.S. 624 (holding jury need not agree on precise theory or means of committing a single unified offense)
State v. West, 238 Ariz. 482 (unanimity and duplicity analysis for §13-3623(A) single unified child-abuse offense)
State v. Buot, 232 Ariz. 432 (affirming preclusion of expert evidence aiming to show impulsivity to negate mens rea)
State v. Payne, 233 Ariz. 484 (discussing single unified child-abuse offense and unanimity principles)
State v. Christensen, 129 Ariz. 32 (limited to premeditated murder context for admissible impulsivity evidence)