From june 2008 until june 2019, the polk county sheriff's office homicide unit maintained a 100% clearance rate on all homicides. Verkko74 cold cases haunt pcso, closures sought. Lakeland — since june 2008, no known homicides committed within the authority of the polk county. Verkkothe producers of oxygen’s “cold justice” looked into the case of glenn pennie. Courtesy of the polk county sheriff’s office.