Updated

A Utah man convicted of killing a teenage baby sitter after a night of sex and drugs that also involved the man's wife has been sentenced to life in prison.

A judge in Ogden said Tuesday that 38-year-old Eric Millerberg took advantage of an immature victim in an especially egregious homicide and then showed callous disregard for the body once the girl died.

A jury last month found Millerberg guilty of child abuse homicide in the 2011 death of 16-year-old Alexis Rasmussen. He was also found guilty of unlawful sexual contact with a minor, obstruction of justice and desecration of a dead body.

Rasmussen's mother told the judge that she suffers every day from the loss of her daughter and struggles to explain to her 7-year-old son where his sister is.

Prosecutors say Millerberg gave the teen a lethal mix of heroin and methamphetamine and then dumped her body in the woods.

During a three-day trial, prosecutors brought detectives, medical examiners, prisoners and Millerberg's wife, Dea Millerberg, to the stand to show that he recklessly injected Rasmussen with lethal doses of heroin and methamphetamine during a night of drugs and sex that also included his wife. Prosecutors told jurors that Eric Millerberg and his wife then dumped her body in the woods of northern Utah while lying to police as the girl's mother desperately searched for her for more than a month.

Dea Millerberg, 40, is awaiting her own criminal trial in April on charges of desecration of a body. She testified against her husband during the trial.

The Associated Press contributed to this report