SACRAMENTO (CBS13) – An investigation is underway after bone fragments were found by a construction crew in Downtown Sacramento.

The discovery was made in the area of 12th and J streets on Tuesday.

Construction crews are working on fixing the sidewalk in front of a FedEx Office building near the intersection. One worker apparently lifted up some concrete and found the bones.

At this point, it’s unclear if the bones are human remains or animal bones. The Sacramento County Coroner’s Office is now investigating.