State v. Guerro, 502 P.3d 338

Defendant Omar Guerro was convicted of murder, aggravated kidnapping (one count), and possession of a firearm by a restricted person after a group shooting at a Moab trailer park left Rojo dead. Witnesses BreeAnna, Jorge, and Jaime testified against Guerro.
Physical evidence connected Guerro to the .40 caliber gun: matching casings at the scene, a .40 casing in his pocket at arrest, a gun tossed from the car, and Guerro’s fingerprint on the gun magazine.
During cross-examination of Neighbor, defense counsel elicited testimony that Neighbor’s sister had received texts from Kevin identifying Jaime as the shooter; the prosecutor then introduced screenshots of those texts to rebut a misleading impression created by defense questioning.
The court admitted the screenshots after finding authentication sufficient and under the curative-admissibility principle (and Rule 806) because the defense had opened the door to the issue.
A DNA report on the gun existed but was not admitted at trial for lack of authentication; Guerro sought to supplement the appellate record with that report but did not pursue remand under Rule 23B.
On appeal Guerro argued (1) the texts were improperly authenticated; and (2) multiple ineffective-assistance claims: failure to challenge the Spanish translation, failure to object to a prosecutor question about witnesses’ veracity, and failure to call a witness about the DNA report. The court affirmed.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Admission/authentication of text-message screenshots	Trial court abused discretion; screenshots unauthenticated	Defense elicited misleading testimony about texts; State could rebut; curative admissibility applies	Admitted properly — defendant opened the door; curative admissibility permits rebuttal evidence
Ineffective assistance — failure to object to Spanish translation	Counsel should have required translator witness for accuracy	No evidence translation was inaccurate; objection likely futile	No deficient performance or prejudice; appellant offered no proof translation erred
Ineffective assistance — failure to object to prosecutor's question about witnesses lying	Question improperly asked defendant to attack witnesses' character and harmed credibility	Failure to object was tactical; defense theory was that witnesses colluded and lied	No ineffective assistance; reasonable trial strategy to permit answer consistent with defense theme
Ineffective assistance — failure to call DNA witness / admit DNA report	Counsel should have presented DNA report/expert to challenge State evidence	DNA report not in record; no showing of what it would have proven; remand needed to supplement record	Claim fails on appeal: appellant didn’t supplement record under Rule 23B, so no showing of deficiency or prejudice

Arnold v. Grigsby, 417 P.3d 606 (Utah 2018) (standard of review for evidentiary admissibility)
Barson ex rel. Barson v. E.R. Squibb & Sons, Inc., 682 P.2d 832 (Utah 1984) (curative-admissibility doctrine; party who injects evidence cannot complain of rebuttal)
State v. Dalton, 331 P.3d 1110 (Utah Ct. App. 2014) (defendant who opens the door allows rebuttal evidence)
State v. Mahi, 125 P.3d 103 (Utah Ct. App. 2005) (same principle: party introducing inflammatory evidence cannot later challenge rebuttal)
Strickland v. Washington, 466 U.S. 668 (U.S. 1984) (two-prong test for ineffective assistance of counsel)
Burt v. Titlow, 571 U.S. 12 (U.S. 2013) (presumption that counsel’s conduct falls within a wide range of reasonable professional assistance)
State v. Litherland, 12 P.3d 92 (Utah 2000) (remand under Rule 23B to supplement record for ineffective-assistance claims)