OGDEN — A suspect’s refusal to give his cellphone unlock code to police is protected by the 5th Amendment, the Utah Court of Appeals ruled in overturning an Ogden man’s three first-degree felony convictions.

During his arrest for the alleged assault of an ex-girlfriend on Aug. 30, 2017, Alfonso M. Valdez would not show investigators his Android phone’s nine-dot-pattern swipe code so they could look for texts that supposedly showed he had been reconciling with the woman.

Police had a search warrant for the contents of the phone, but they never got access to the data because of Valdez’s refusal.

In its ruling issued Thursday, the Court of Appeals said Valdez’s right against self-incrimination was violated when 2nd District Judge Joseph Bean in Ogden allowed a detective to testify about Valdez’s withholding of the code.

His rights were further violated, the court in Salt Lake City ruled, when Weber County prosecutors argued the jury should infer that Valdez’s refusal meant that no “make up” texts existed.

The jury convicted Valdez, now 55, of first-degree felony counts of kidnapping, robbery and aggravated assault and Bean sentenced him to three terms of five years to life in the Utah State Prison, where he remains incarcerated.

After attorneys argued about the swipe code refusal during the trial, Bean said “the Fifth Amendment does not necessarily protect” such a refusal. But the appeals court ruled, “Communicating a cell phone swipe code to law enforcement is a ‘testimonial’ act protected by the Fifth Amendment.”

Quoting U.S. Supreme Court precedent, the court said the amendment “reflects a judgment that the prosecution should not be free to build up a criminal case, in whole or in part, with the assistance of enforced disclosures by the accused.”

With modern technology, that applies to cellphone codes, the court said.

The amendment forbids “either comment by the prosecution on the accused’s silence or instructions by the court that such silence is evidence of guilt,” the Court of Appeals said.

One of Valdez’s main defenses was his claim, supported by testimony by his ex-wife, that his encounter with the former girlfriend had been friendly, not adversarial, and was preceded by a sexually charged text exchange discussing reconciliation.

In closing arguments, prosecutors pointed out no such messages were in evidence. They urged jurors not to believe the ex-wife’s statement that she had seen the texts. Then they described Valdez’s refusal to give up the pass code.

The ex-girlfriend testified Valdez threatened her with a gun and a knife when she got into his car. She said he also pulled her hair and put his hand around her neck before she was able to escape.

The court noted police never found a knife and the woman’s cellphone, and that the gun was a starter pistol, incapable of firing live bullets.

The woman also had only a small cut on her lip and no other injuries, court documents said.

The ruling sends the case back to the district court for a possible new trial.