Detective Nick Williams looks into whether they have the guilty culprit after an eyewitness points out a potential suspect at a crime scene; an armed gunman hides in his apartment after killing two men; a man is shot at his sister's home.

Detective Ryan Vaught believes a homeless man was murdered in cold blood; Detective Drew Deacon finds a lead after a father is brutally shot; a gunman shoots an AK-47 on the highway; Detective Nick Williams talks to an at-risk individual.

A high school student in New Orleans gets shot on his way to school; a shooting suspect in St. Louis is found walking down the street naked; detectives in Tulsa, Okla., wonder if carjackers were involved in the murder of a single father.