Aidan Zellmer Case: Charges, Plea Deal, and Life Sentence

The Aidan Zellmer case ended in March 2019 when a 16-year-old from Thornton, Colorado, was sentenced to life in prison with the possibility of parole after 40 years for the June 2017 murder of 10-year-old Kiaya Campbell. Zellmer, who was 15 at the time of the killing, pleaded guilty to first-degree murder after deliberation. He beat Kiaya to death with a metal pipe and then lied to police and search teams about what had happened to her.

What Happened to Kiaya Campbell

On the evening of June 7, 2017, Zellmer and Kiaya left her father’s home in the 12400 block of Forest Drive in Thornton. The two children lived together: Zellmer’s mother was in a relationship with Kiaya’s father.¹ According to the arrest affidavit, Zellmer had damaged some of Kiaya’s Pokémon cards, and the two left the house on the pretext of stealing replacements and candy from a nearby shopping center.²

Zellmer struck Kiaya in the head five times with a metal pipe and dragged her body into a drainage ditch behind homes near 128th Avenue and Jasmine Street. An autopsy confirmed she died of blunt-force injuries to the head and had additional wounds to several fingers. Her body was found naked from the waist below, and investigators noted evidence suggesting sexual assault. The murder weapon was never recovered, though Zellmer later told others he had used a “metal object.”¹

How Police Identified Him

Kiaya was reported missing that same evening. Zellmer told police and searchers that the two had become separated during a thunderstorm while walking home, and he led investigators to incorrect locations, sticking to his account even after officers told him it didn’t add up.¹ Kiaya’s body was found the next day, roughly 1.5 miles from her father’s home. When police confronted Zellmer with the discovery he reportedly “erupted with emotion” but still denied hurting her, saying he “left her because she was being annoying.”³

Forensic testing did what the interviews could not. Blood and DNA evidence were found on Zellmer’s shoes and clothing, and he was arrested on the night of June 10, 2017.³ Adams County District Attorney Dave Young later described his demeanor during the initial interviews as “calm, cool and collected.”⁴

Charges and Transfer to Adult Court

Charges were filed in juvenile court on June 14, 2017. Zellmer was accused of two counts of murder — first-degree murder with intent to kill after deliberation, and first-degree murder of a child under 12 by a person in a position of trust — along with three sexual assault charges.⁵⁶ Young announced at the first hearing that he would prosecute Zellmer as an adult, and on January 23, 2018, Adams County Juvenile Court Judge Priscilla Loew granted the transfer.⁷

The Plea Deal

On February 1, 2019, Zellmer pleaded guilty to one count of first-degree murder after deliberation. Prosecutors dropped the second murder count and all three sexual assault charges.²

Young offered two reasons. The evidence supporting the sexual assault charges was weaker than the homicide evidence. And dropping them preserved Zellmer’s eligibility for a Colorado Department of Corrections rehabilitation program that excludes anyone convicted of a sex offense. Young also pointed out that the sentence itself would not change: Colorado law made Zellmer, as a juvenile offender, automatically eligible for parole after 40 years whether the case ended in trial or plea.⁶ He said Kiaya’s family had “some concern” about the arrangement but ultimately felt “a sense of relief that they have some closure.”⁸

The Sentence

Adams County District Judge Sharon Holbrook sentenced Zellmer on March 11, 2019, to life in prison with the possibility of parole after 40 years. Young said that with good behavior Zellmer could become eligible in 30 years.¹ Zellmer was 17 at sentencing and was to be held in a youth detention facility until turning 18, then transferred to the Department of Corrections.³

Young told the court that Zellmer had never taken responsibility during the entire legal process.¹ Defense counsel argued for leniency, citing Zellmer’s mental health issues, troubled family history, and alleged abuse.⁹ The judge imposed the agreed sentence.

What Parole Eligibility Actually Means

Under the standard terms of his sentence, Zellmer would be eligible for parole after 40 years, around 2057, or roughly 30 years with good behavior. There is also a separate path through the program the plea deal was structured to protect: the Juveniles and Young Adults Convicted as Adults Program (JYACAP), created by Senate Bill 16-180. It lets people convicted of serious crimes as juveniles petition for early parole after serving a minimum number of years — 25 years for most first-degree murder convictions.¹⁰

The program does not guarantee release. Participants have to complete a multi-phase curriculum with education requirements and career certification, hold a high school diploma or equivalency, show acceptance of responsibility, and maintain positive institutional behavior. Once they finish, the parole board makes a recommendation to the Governor, who holds the final release authority. Anyone convicted of a sexual offense is ineligible.¹¹

Kiaya’s Family

Kiaya’s family filled the courtroom at sentencing in teal and pink, her favorite colors. Attorneys played a video of her dancing and singing, and relatives spoke about her smile and her “goofiness.” Her mother, Chantel Campbell, told the court 40 years was “not enough” and described watching Zellmer sit through proceedings appearing “emotionless.” Her grandmother, Julie Beery, said she would have preferred the death penalty: “We only got 10 years. Ten wonderful years, but that’s not enough and not for this reason.” Kiaya’s grandfather said the child welfare system may have failed Zellmer, but “it failed the Campbell family, too.”¹

1
The Denver Post. Kiaya Campbell Murder: Aidan Zellmer Sentenced
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KDVR. 16-Year-Old Sentenced to Life in Prison for Death of 10-Year-Old Thornton Girl
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Oxygen. Aidan Zellmer Colorado Teen Sentenced Murder Kiaya Campbell
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KOAA. Sixteen-Year-Old Sentenced to Life in Prison for Death of Kiaya Campbell
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The Denver Post. Kiaya Campbell Death Charges Teen Suspect
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The Denver Post. Kiaya Campbell Murder: Aidan Zellmer
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Denver7. Teen Who Pleaded Guilty to Murdering Kiaya Campbell Sentenced to Life in Prison
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CBS News Colorado. Aidan Zellmer Pleads Guilty Murder Kiaya Campbell
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WBAL-TV. Teen Who Beat 10-Year-Old Girl to Death With Pipe Gets Life in Prison
10
Colorado General Assembly. SB 16-180: Department of Corrections Program for Juvenile Offenders
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Colorado Department of Corrections. FY 2024 Juvenile and Young Adult Reintegration Program Status Report