Pre-emptive Strike / Unlucky - S4.E4

In Memphis, TN, Lt. Toney Armstrong and his team respond to a shooting where the killer may be barricaded in his apartment. Then the stand-off gives way to a dispute among friends where detectives must determine if the shooter was acting in self-defense, or not. And in Dallas, TX, Detectives Kim Sanders and Paul Ellzey start with nothing but a decomposed body, and are quickly drawn into a fast-paced manhunt to track down a mentally unstable suspect who they're afraid might hurt someone else.