WAUWATOSA, Wis. (AP) — The Milwaukee County coroner says a human skull that contractors discovered during a basement excavation in Wauwatosa is estimated to be decades old.

The Medical Examiner’s Office said Monday the skull’s condition and material found with it led to the estimate. The skull is being sent to the University of North Texas Center for Human Identification for further analysis.

The land where the skull and bone fragments were found Friday has been vacant for three years and the property owner recently got approval from the city to build a new house on the site.

Wauwatosa police Lt. Brian Zalewski says investigators are waiting for results from the analysis in Texas to determine how to proceed.