The remains were discovered November 28 on private property near the Last Chance Mountain Range, according to a BLM news release.
The agency has offered $10,000 for information leading to the arrest and conviction of the person(s) responsible.
The Last Chance Mountains are in the Johnnie HMA, the lawful home of wild burros.
The HMA is not subject to permitted grazing.
Private lands are shown in white in the following map from the National Data Viewer.