BRIGHTON, Colo. (CBS4) – The Adams County coroner is providing more details about how a 10-year-old girl in Thornton was killed over the summer.

Kiaya Campbell (credit: Thornton Police)

The coroner says Kiaya Campbell died from blunt force injuries to the head due to an assault. There were many lacerations and fractures to her head that caused her death.

Police found Campbell’s body on June 9 in a drainage ditch approximately a mile away from her home. They arrested Aiden Zellmer, a 15-year-old boy who lived in the same house, for murder. Zellmer’s mother was in a relationship with Campbell’s father at the time.

Aidan Zellmer (credit: CBS)

The district attorney is working to charge the teen as an adult. There will be a hearing on that matter on Oct. 30.

So far there’s no official word on what a motive might be for the crime.