But Utah Supreme Court Associate Chief Justice Ronald Nehring wrote in the unanimous ruling released Friday that Adkins had abused his discretion as a judge by granting the retrial.
"The possibility that any of the alleged errors impacted the verdict is so remote that it was anabuse of discretion to arrest the judgment and grant a new trial based on cumulative error," Nehring wrote.
In December, the high court overturned Adkins' ruling in another case involving a female school employee accused of having sex with a male student.
Jamie Greenwood, 44, a cafeteria worker at Eastmont Middle School in Sandy, had asked for her case to be heard by a judge instead on a jury.
Prosecutors cried foul when Greenwood, on the morning her jury trial was to begin in August 2010, asked Adkins to hear her case instead. Her attorney argued that a trained legal mind would be better able to parse the fine line between, for example, rape and unlawful sexual activity, and that the jury pool was tainted by pretrial publicity.
Adkins granted the request, but prosecutors appealed to the Utah Supreme Court.
The high court ultimately sided with the state, finding that defendants don't have the right to choose a judge over a jury unless prosecutors agree to the change. Greenwood has a review hearing next Thursday before 3rd District Judge Charlene Barlow.
In Billingley's case, Adkins granted a new trial, in part, because jurors were not allowed to hear testimony from another teacher at the middle school who claimed one of the alleged victims had made sexual advances towards her.
The art teacher told the school principal that the teenager had sexually propositioned her at the school, but her testimony was not allowed at trial because of a state law that protects victims of sexual abuse from having aspects of their sexual history discussed in court as a way to discredit them.
Adkins also ruled that a nude photo of Billingsley's breast sent to the boys from her cellphone should not have been used as evidence because attorneys couldn't prove when or why the photo was taken. Billingsley's attorneys had argued the photo could have unfairly influenced the jury into believing that Billingsley took the image to seduce her alleged victims, when she claimed she took the photo for her husband and the boys stole her phone to set her up.
Adkins also cited other errors, including Billingsley being referred to as a "teacher" instead of an "aide"; the prosecutor thanking one of the witnesses "for their honesty"on the stand; and a state employee who "emphatically" shook her head from side to side during Billingsley's testimony.
Billingsley's retrial has been delayed as the Supreme Court debated the appeal filed by the Utah Attorney General's Office on behalf of the Salt Lake County District Attorney's Office.
Billingsley will be in court on May 16 for a status conference with Judge Barlow.
Two teenage boys testified at Billingsley's 2010 trial that she performed sex acts on them in 2009. The first victim testified she performed oral sex on him during in-school suspension while another student slept in a nearby desk. He testified that the following summer, after he was no longer a student at the school, he was with a friend, also 15 at the time, when he and Billingsley had a phone conversation on the friend's phone. Billingsley then sent pictures of her breasts to the friend's cellphone, the teens claimed.
The boy and his friend both said they then joined Billingsley in her SUV at a West Jordan park. Both teens claimed she fondled them and committed other sex acts with them in the backseat. The second teen said he got out of the car when Billingsley and the first teen began to have sex.
Billingsley denied the sexual encounters, saying the two teens made up the story.