State of Arizona v. Sergio Fierro Jr, 517 P.3d 635

In 2018 Sergio Fierro stabbed J.H. repeatedly in an RV with a six-inch spade drill bit and later stabbed P.P.; police subdued and arrested him; J.H. was hospitalized.
Fierro was charged with two counts of aggravated assault (deadly weapon), two counts of aggravated assault causing temporary but substantial disfigurement, and attempted second-degree murder of J.H.
At trial the court gave an instruction stating attempted second-degree murder could be founded on intent to kill, or on knowingly causing serious physical injury, or on recklessness; Fierro’s counsel did not object. The prosecutor repeatedly argued the State’s case required intent to kill; Fierro argued self-defense.
The jury convicted on all counts; the trial court imposed concurrent sentences for the assaults and a consecutive 15.75-year term for attempted second-degree murder.
The court of appeals held the instruction was fundamentally erroneous but found no prejudice and affirmed; the Arizona Supreme Court granted review to settle the proper instruction and decide prejudice.
The Supreme Court held the instruction was legally erroneous, adopted a standalone attempted-second-degree-murder instruction requiring intent to kill, but concluded Fierro failed to prove prejudice under the fundamental-error standard and affirmed his conviction and sentence.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Proper mens rea for attempted second-degree murder	State: attempted second-degree murder requires the defendant intended to kill; courts should adopt an instruction so requiring	Fierro: trial instruction was erroneous because it allowed conviction without intent to kill; requested reversal	The Court: Instruction as given was legally erroneous; adopts a new instruction limiting attempted second-degree murder to intent to kill (no recklessness/intent to cause serious injury)
Prejudicial error (fundamental-error review where no trial objection)	State: no prejudice — prosecutor consistently argued intent to kill, defense was self-defense (did not contest intent-to-kill element), evidence supports intent to kill	Fierro: prejudiced because erroneous instruction relieved State of its burden and defense testimony/counsel placed his mens rea at issue (could have led jury to convict on non-existent theory)	The Court: No prejudice shown — under Escalante the defendant must show a reasonable jury could have reached a different verdict; here the State’s consistent theory, evidence, and defense posture made it implausible jury convicted on the erroneous grounds; conviction affirmed

State v. Ontiveros, 206 Ariz. 539 (App. 2003) (explains attempt requires intent to commit the target offense and rejects attempted reckless second-degree murder)
State v. Curry, 187 Ariz. 623 (App. 1996) (recognizes there is no offense of attempted reckless second-degree murder in Arizona)
State v. Dickinson, 233 Ariz. 527 (App. 2013) (applies prejudice analysis where erroneous attempted-second-degree-murder instruction was given)
State v. Juarez-Orci, 236 Ariz. 520 (App. 2015) (reversed where defense implicated lesser mens rea and jury could have convicted on non-existent theory)
State v. Escalante, 245 Ariz. 135 (2018) (articulates framework for proving prejudice from unobjected-to fundamental error)
State v. Felix, 237 Ariz. 280 (App. 2015) (assesses whether defense arguments implicated the erroneous instruction and potential prejudice)
State v. Murray, 250 Ariz. 543 (2021) (reiterates constitutional significance of the State’s burden and jury instructions)
Taylor v. Kentucky, 436 U.S. 478 (1978) (prosecutor’s correct statement of law cannot cure an erroneous court instruction)
Henderson v. Kibbe, 431 U.S. 145 (1977) (discusses standards for harmless-error review)