CODY, Wyo. (AP) — Authorities are investigating possible theft from a site in northwest Wyoming where the apparent skeletal remains of an ancient mammoth were found.

Carlie Ronca, Wyoming area manager for the federal Bureau of Reclamation, says the site might have been disturbed before it was reported to the agency last week.

The remains, which include rib, vertebrae and other parts, were uncovered and found by a hiker after the level of Buffalo Bill Reservoir was lowered as part of normal operations. The Bureau of Reclamation and Wyoming's archaeologist are working to remove the fossils before the reservoir rises from spring snowmelt.

Photos of the discovery show the fossils to be in poor condition, eroding away after being exposed to the elements.