Police are investigating a human skull that was donated to a Goodwill in Goodyear on Tuesday.

Police officers responded to the Goodyear Goodwill near Yuma Road and Sarival Avenue after reports that a human skull was found in a donation box with taxidermy items.

Police took the skull to the medical examiner’s office for further examination. Officials at the agency determined the skull to be a historic human skull and likely is not associated with a crime.

Police believe the donation box was dropped off at the thrift store sometime over the weekend. Employees opened the box on Tuesday.

No other information was made available. The full investigation is ongoing.