Chilling new leaked footage appears to show convicted University of Idaho killer Bryan Kohberger with red hands pacing his concrete cell — prompting the maximum security prison where he’s locked up to probe the video’s source.

Kohberger, 30, was moved to the Idaho Maximum Security Institution, south of Boise, just hours after being sentenced to four consecutive life sentences in July. He pleaded guilty to the first-degree murders of Madison Mogen and Kaylee Goncalves, both 21, and Xana Kernodle and Ethan Chapin, both 20.

The footage began circulating on social media Thursday and appears to depict Kohberger in prison clothing walking back and forth in a cell.