Season 3 Preview: "Trader Trent's" following on Facebook Marketplace opened up a range of possibilities for detectives.

Alex Sowa, Jim Sowa's son, tearfully recalls finding his father's body.

Preview: Carmela Knight, a "suburban hockey mom", was found dead after a house fire surrounded by drug paraphernalia. What happened?

Preview: It is quickly discovered that Carmela Knight died from blunt-force trauma before being badly burned in a house fire.

Friends and family tearfully recall the night that led to Carmela Knight's death.

Walker's frantic 911 call, firefighters on the scene recognize Lt. William Walker, a fellow firefighter.

Learn more about murder victim Scott Sessions and the shocking circumstances that followed when authorities tracked suspects Heather Frank and Kevin Eastman.

Learn more about how medical examiners determine the manner of death ahead of the Season 5 return of Oxygen's Accident, ...

Learn more about Patricia McDermott's fatal shooting in Philadelphia, and what police later found out about her killer Juan ...

Learn more about what happened to Karen Swift after she vanished following a 2011 Halloween party in Dyersburg, Tennessee, ...

Learn more about Joyce Mitchell's life after helping Richard Matt and David Sweat escape from the Clinton Correctional ...

Lt. William Walker's fellow firefighters speak out about his tragic death and how they dealt with the aftermath of his ...