Teen girl, boyfriend sentenced for killing girl’s father

In May, Sierra Halseth and Aaron Guerrero admitted to killing 45-year-old Daniel Halseth, attempting to set his house on fire, and taking his car and debit card to flee to Salt Lake City.

Halseth’s burnt body, stabbed and cut 70 times, was found in the garage of his northwest Las Vegas home on April 9, 2021, and the teenagers were detained in Salt Lake City four days later.

District Judge Tierra Jones sentenced Sierra and Guerrero to life in prison with the possibility of parole after 22 years. The defendants also were ordered to pay $5,000 in restitution.

“This is a very, very tragic situation,” Jones said. “I wish that there was something that I was going to say or something that I could do that would stop all the suffering that is going on.”

Sierra was 16 at the time of the killing. Guerrero was 18, but Clark County Detention Center records show that he is now 20.

The two defendants pleaded guilty to all the counts they faced: murder with a deadly weapon, conspiracy to commit murder, arson, robbery with a deadly weapon, conspiracy to commit robbery and four counts of fraudulent use of a credit or debit card.

Court records indicate that Sierra and Guerrero dated from June 2020 to December 2020, when their parents stopped them from seeing each other after learning that the teenagers planned to leave for Los Angeles together.

Allegations of abuse

The day before Halseth’s body was found, Guerrero ran away from home, and the teenagers later purchased a circular saw, saw blades, bleach, lighter fluid, disposable gloves and drop cloth from stores near Halseth’s home, according to arresting documents. Hundreds of dollars also were withdrawn from one of Halseth’s bank accounts.

After police arrested the couple, investigators found a video on Sierra’s phone showing the couple giggling and discussing what officials said was her father’s killing.

During the sentencing hearing on Thursday, Sierra read from a statement while addressing the judge. In the statement, Sierra alleged that her father abused her sexually and physically, and pushed her to drink alcohol.

“My biological father has traumatized me — trauma I still have to work through every day,” Sierra told the judge.

When Guerrero addressed the judge, he apologized to Halseth’s family.

Michael Sanft, Sierra’s defense attorney, told the Las Vegas Review-Journal that the evidence in the case did not allow him to corroborate all of Sierra’s claims about her father.

However, Sanft said, “there had to have been a reason” for the killing.

“I don’t think anyone here says this was not horrible,” the attorney said. “It was just the fact that there was more to the story.”

Divorce, custody dispute

Sierra’s parents had gone through a bitter divorce, court records show. Sierra’s mother, who now goes by the name Elizabeth Helgelien, had been granted primary custody after Halseth filed for divorce in 2011, but the girl’s parents began disputing custody arrangements in 2020.

Child Protective Services interviewed Sierra at one point, according to court records. In videos of Family Court hearings previously obtained by the Review-Journal, Family Court Judge Charles Hoskin said, “Something else is going on with Sierra.”

“I don’t know yet what that is, whether that’s parental alienation, whether that’s human trafficking, whether that’s manipulation,” Hoskin said during an October 2020 hearing. “And I don’t know who at this point is to blame for that.”

In October 2011, Halseth was arrested on suspicion of open and gross lewdness after Helgelien said he assaulted her, according to an arrest report. He pleaded guilty a year later to misdemeanor counts of coercion and battery, and was sentenced to six months’ probation.

Helgelien told the Review-Journal on Thursday that she believed what her daughter said about her ex-husband, and that she wanted Sierra removed from his home.

“The system failed her at every turn. They could have saved her, and they failed her,” Helgelien said.

Three of Halseth’s siblings and his mother spoke during the sentencing hearing, expressing anger at Sierra. Following the hearing, Halseth’s mother, Christine Halseth, said her granddaughter’s statement about him was “nothing but a lie.”

Multiple family members told the judge on Thursday that they wished Sierra had received the death penalty.

Ben Halseth, one of the victim’s brothers, showed the judge posters full of pictures of Daniel Halseth when he was young. He said his brother was a “great father,” and “all he wanted in life was to be a good dad to his kids.”

Tom Halseth, another brother, cried as he addressed the judge. He said Sierra and Guerrero took something away from him that he cannot ever get back.

“I can hear my brother asking me to forgive. And to be honest, I’m not sure that’s even possible,” Tom Halseth said.

Contact Katelyn Newberg at knewberg@reviewjournal.com or 702-383-0240. Follow @k_newberg on Twitter.