FREDERICK, Md. — UPDATE: Authorities found and took William Glenn Smith back into custody in Martinsburg, West Virginia on Monday.
Guards noticed Smith missing on Monday morning when he didn't show up for work.
When detention staff checked his cell, they noticed the window was removed.
Surveillance footage later showed that Smith escaped around 8:30 p.m. Sunday night.
Smith had allegedly put items under his bed blanket to make it look like the shape of a body, which made staff think he was in his cell when he really wasn't.
Officials say Smith was last seen physically at 8 p.m. Monday during a standard inmate walk through headcount.
He'd been serving time at an adult detention work release facility since March 4 for assault and false imprisonment.
Smith was last seen wearing a black sweatshirt and black pants, heading in the direction of Rt. 85.
Police warn that if you see him, do not approach and call 911. Anyone with information can call Corporal Harry Sier at 301-600-7149. Anonymous tips can be left on the tip line at 301-600-4131.