An 'ancient' human skull was dropped off in a donation box full of taxidermy items to an Arizona Goodwill store

• Someone dropped off an "ancient" human skull inside a donation box at an Arizona Goodwill.
• "It's very bizarre," a spokeswoman for the Goodyear Police Department told Insider of the situation.

A recent donation to a Goodwill store in Arizona included something extra unusual — an "ancient" human skull, local authorities said.

The skull, along with a serial-numbered prosthetic eye, was discovered inside of a box full of taxidermy items and faux animal bones that someone had dropped off at a Goodwill in the Maricopa County city of Goodyear, according to police.

"It's very bizarre," Goodyear Police Department spokeswoman Lisa Berry told Insider on Friday, adding, "We have not seen something like this before."

When staffers at the Goodwill store went through the donated box on Tuesday and found what they quickly believed to be a human skull, they called police to report it.

A spokesperson for Goodwill of Central & Northern Arizona told Insider: "Our store team followed protocol by immediately reporting the donation to the Goodyear Police Department" and added that Goodwill is cooperating with authorities.

Investigators with the Goodyear Police Department had the skull sent off to the Maricopa County medical examiner's office, which did "confirm that it is in fact a human skull," Berry said during a press conference this week.

Berry said the skull appears to be "historic" and "ancient" and that at this time authorities don't believe that the skull is linked to any crime.

"It does not appear to have any forensic value at all," Berry said.

The skull remains in the possession of the medical examiner, which is still carrying out its investigation, Berry told Insider.

"Once the findings come back from the medical examiner's office, then we'll know what we have," she said, adding, "There's no crime associated with it based on what they know now."

Berry noted that it's not necessarily a crime for a person to possess a human skull. But she added that a "grave-robber type of situation" could be different.

"If people are out there, you know, digging up graves, that would be a crime," Berry told Insider. "But we have nothing to go on at this point to determine that that's the case."

At this point, it remains a mystery where the skull came from.