Season 4

A college student is strangled to death in her Bryan, Texas, apartment. Investigators are hard-pressed to find anyone who would want to kill such a bubbly and dynamic woman, but DNA discovered on the scene proves there’s at least one person who wanted to do her harm.

After his contentious divorce, Josh Niles finds love with Amber Washburn. Josh’s kids join their new family in Sodus, New York, and life seems like a fairytale until a determined gunman shatters their happily ever after.

A 911 call from a worried ex-boyfriend sends police to the Powder Springs, Georgia, home of Danielle Marshall. Once there, they find her shot dead in the kitchen. As the suspects multiply, it takes some police ingenuity to nab the killer.

Mary loves her 40-year marriage and her thriving chiropractic practice in Whitesboro, New York. Then, she falls ill at work and dies two days later. An autopsy points to poisoning, and a mysterious letter implicates someone close to her.

A college student's effervescent personality wins him many admirers on his Columbia, Missouri, campus right up until the day of his murder. As a police search for suspects, a tip leads them to someone with a lot to lose.

Sixteen-year-old Cassie Jo Stoddart is housesitting in a Pocatello, Idaho, neighborhood. As she watches movies on the couch, Cassie is oblivious to the fact that she's not alone. When she finally realizes that someone evil is lurking, it's far too late.

A Nebraska woman fights for her life against a brutal killer – and loses.

On a quiet summer night in 2010, a killer shoots dead a wealthy La Crosse, Wisconsin, couple in their living room. Police look to their financially strapped children for the motive to kill, but a strange discovery may veer them in a whole new direction.

Divorced soccer mom Paige Birgfeld's disappearance catapults her ex-husbands to the top of the suspect list - but when one of them provides a tantalizing clue about Paige's risky secret life, the number of potential culprits explodes.

A St. Charles, Missouri, businessman dies violently at work, and police suspect it was a business deal gone bad. Then they discover several insurance policies plus a secret double life, and their investigation veers into a whole different lane.

Gary and Jan Tyrrell are avid collectors of gold and silver coins and artifacts. Then they turn up dead, and investigators must find out exactly who knew about their expensive hobby - and who would be willing to kill for it.

In Tulsa, Oklahoma, taxi driver Rafael Hernandez's community reveres him as a caring and generous entrepreneur. Then, police pull his cab from a local river with Rafael inside, and the race is on to find his killers before they strike again.

Retired mortgage broker Alan Helmick’s blissful life comes to a violent end while enjoying a cup of coffee at his country home in Colorado. He has no known enemies, but when police find a gun, it’s clear someone close to Alan is an expert in murder.

In Austin, Texas, a concerned son finds his beloved music teacher mother murdered in her bedroom. Within days, the victim's neighbor comes forward with some chilling evidence. Then, two more homicides convince police that a serial killer is on the loose.

After being stabbed at his Marietta, Georgia, home, beloved son Mitchell Jones dies at the hospital. Mitchell is a popular gay man, so police have several potential suspects. It isn't until they employ a new tracking tool that the case breaks wide open.