A 10-year-old girl found dead in a Thornton greenbelt in June was beaten to death, 9Wants to Know has learned.

Kiaya Campbell, who had been reported missing the night before her body was discovered on June 8, suffered multiple blunt force injuries to the head – some of which caused skull fractures – as well as wounds to several fingers, according to an autopsy report.

Two days after the girl’s body was discovered, Thornton police arrested 15-year-old Aiden Zellmer.

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He faces two counts of first-degree murder and is scheduled to appear in court on Oct. 30 for the beginning of a hearing to determine whether the case should be transferred to adult court.

At the time Campbell was reported missing, her family told police that she and a 15-year-old boy had left a home in the 12400 block of Forest Drive in Thornton to walk to a nearby shopping center – then became separated in a rain storm.

She was reported to have last been seen in the 12900 block of Colorado Boulevard.

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The report sparked a massive search in the area for the girl – a search that ended late the next afternoon when a man discovered her body in a natural area roughly a mile east of the area where she was reported to have disappeared.

The autopsy report, released by Adams County Coroner Monica Broncucia-Jordan after an open records request by 9NEWS, details a horrific series of injuries – multiple open lacerations on the right side of the girl’s head, many directly connected to skull fractures.

It also described multiple injuries to her hands, including a broken finger and other contusions.

The report does not indicate what caused the wounds.

Contact 9NEWS reporter Kevin Vaughan with tips about this or any story: kevin.vaughan@9news.com or 303-871-1862.