Authorities are investigating the discovery of a human skull in Phoenix's South Mountain Preserve.

Phoenix police said a hiker stumbled upon the skull last Saturday afternoon and notified authorities.

According to police, the skull showed what appeared to be trauma and homicide detectives were called in to take over the investigation.

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The skull has been turned over to the Maricopa County Medical Examiner’s Office to determine a possible cause of death.

Police also are working with missing persons detectives in hope of identifying the person who died.