The First 48 (2004)

Season 1: Episode 7

Employees of an ice rink arrives at work only to find the door ajar and blood all over the floor. When the police arrive the overnight employee is found beaten beyond recognition and the facility robbed. Since who ever did this seemed to have knowledge detectives turn to former employees to start the investigation. In another case a woman walking by a river in Phoenix she's what she believes in a body wrapped in plastic in the water. Detectives don't have an identity, or crime scene making this a difficult investigation.