Klingaman was a federal prisoner staying at the halfway house at 605 Main in Davenport.
Klingaman reportedly failed to return after leaving Monday, January 9, 2012 to seek employment.
Police said Klingaman has been seen on the Illinois side of the Quad Cities since his escape.
“Klingaman should be considered dangerous since he has a history of being armed,” said a statement from police.
“Zach has tattoos on the right side of his neck and a woman’s portrait on his chest,” police said. He is six feet tall and weighs about 150 pounds. He has a slender build, blue eyes and brown hair.
Anyone with information about Klingaman should not approach him. Instead, contact Crime Stoppers of the Quad Cities on their tip line – (309) 762-9500.