BRIGHTON, Colo. (CBS4) – On Friday 16-year-old Aidan Zellmer pleaded guilty to killing 10-year-old Kiaya Campbell in Thornton in 2017. Zellmer was 15 at the time of the shocking Adams County crime.

Aidan Zellmer (credit: CBS)

Zellmer was with Campbell the night she disappeared in June 2017. His mother was in a relationship with Campbell’s father at the time.

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Kiaya Campbell (credit: CBS)

Zellmer had claimed the two had been separated in a rainstorm and a search was launched for her. Campbell’s body was found the next day in a drainage ditch behind homes near 128th Avenue and Jasmine Street. The Adams County Coroner’s Office found she had been beaten to death.

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(credit: CBS)

Adams County District Attorney Dave Young said there was some concern from Campbell’s family when they heard that there might be a plea deal in the works. But he said the sentence Zellmer will get as part of his deal is the same as the one he would have gotten if a trial had taken place and ended with a conviction.

“A 10-year-old’s life it gone, and her parents are going to be without her for the rest of their lives. So I think there’s a sense of relief that they have some closure in the criminal justice center. But nothing we do here today is going to bring them absolute relief for what happened to their daughter,” Young said.

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Zellmer will be sentenced on March 11. As part of his deal, he’ll be in a youth detention facility until he’s 18 and continue a prison term after that. His family is hopeful he’ll get into a juvenile offender program for minors tried as adults with lengthy sentences. That could bring his eligibility for parole down from 40 years to 30 years.