Miera pleaded with Hadley to sentence Eric Millerberg, the man recently convicted of causing Alexis' death, to the maximum penalty for injecting the girl with lethal amounts of methamphetamine and heroin and then dumping the teen's body in September 2011.
"I don't think there is any hope that he will change," Miera said of 38-year-old Millerberg. "I would like to see him stay where he belongs so he can't hurt anyone else."
Millerberg was found guilty in February of child-abuse homicide, obstructing justice, desecrating a human body and having unlawful sexual activity with Alexis.
After the girl died of an apparent overdose, Millerberg and his wife, Dea Millerberg, got rid of the body by dumping it in a remote area.
Millerberg's attorney, Randall Marshall, argued that the man's sentences on each count should run concurrently to one another because all of the crimes occurred during one "criminal episode," adding that the girl's death was an accident.
Marshall also argued that Millerberg's wife should shoulder some of the blame for the girl's death.
"All the blame now rests of Mr. Millerberg for this death," Marshall said. "That by itself hardly seems fair. He's essentially being saddled with all the burden, all the responsibility for Lexi's death."
But Deputy Weber County Attorney Christopher Shaw told the judge that the death was no accident because Eric Millerberg intentionally injected the drugs into the teen girl. He asked for consecutive prison sentences for the man.
"This young lady is gone, and it's a result of his conduct," Shaw said. "Things don't get any worse than this, judge."
Ultimately, Hadley sentenced Eric Millerberg to the maximum sentence, ordering all four convictions to run consecutively: five years to life for the child-abuse homicide, one to 15 for obstructing justice and terms of zero to five years for the desecration and unlawful sex convictions.
"Intentionally injecting a young lady with dangerous drugs multiple times is beyond reckless," Hadley told Millerberg. "… She was simply an immature victim you took advantage of after you injected her with drugs."
Before the sentence was handed down, Eric Millerberg apologized, saying he was sorry for what happened to Alexis.
"I'm willing to shoulder the responsibility for the role I played and the things that I have done," he said, adding: "There's no way [the responsibility] is all mine."
Marshall said outside of court that Eric Millerberg claims his wife injected the drugs into Alexis that night, not him.
During Eric Millerberg's three-day jury trial, Dea Millerberg took the stand and testified against her husband of nearly 10 years.
She recounted that on Sept. 10, 2011, she picked up Alexis to baby sit their kids, but instead she got high with the teen and her husband.
Through the night, Eric Millerberg injected Alexis three times, Dea Millerberg testified once in the teen's neck. The three also attempted to have sex together, the woman testified, but they were too high.
Shortly after her husband injected Alexis for the third time, Dea Millerberg testified that the teen began to complain of being cold and shaky. The teen took a bath, and afterward, the Millerbergs helped her into the couple's bed, then the adults went outside to smoke.
When they returned, they found Alexis was not breathing. Dea Millerberg, who was at the time a licensed nurse, said she attempted CPR, but the girl never responded.
In a panic, the Millerbergs weighed their options. Ultimately, they decided to dump the teen in a remote part of Morgan County near the Taggart exit of Interstate 84.
Marshall did not call any witnesses to the stand during the trial on behalf of Eric Millerberg, but attacked Dea Millerberg's testimony in his closing argument, saying it was inconsistent.
Eric Millerberg did not testify in his own defense at trial.
Alexis was missing for 38 days before Eric Millerberg's friend, Eric "Peanut" Smith, broke the case for police. He testified that he helped Eric Millerberg move the girl's body on Sept. 12, 2011 a day after the Millerbergs initially dumped it.
Smith led police back to the girl's badly decomposed body in October 2011.
The girl was found with her legs folded against her in a fetal position, her lower half stuffed into a garbage bag.
Dea Millerberg, 40, is charged with third-degree felony desecration of a human body related to the girl's death. She has a scheduling hearing on March 26. She was granted "use immunity" in her husband's trial, meaning her testimony can't be used against her.
Charges were never filed against Smith, who made a deal with police in exchange for leading them to the girl's body.