A Time to Kill

As detectives reconstruct a single mom's final 24 hours, their suspicions turn to her fiancé, a creepy co-worker, and a violent ex-boyfriend. Ultimately, investigators discover a disturbing pattern of attacks -- and a predator with the master key. [also shown as S6:E23]

When Florida investigators find a retired Marine beaten then slain by a shotgun blast in his home, their suspect list grows from his estranged son to a mystery woman he'd just met -- to a possible serial killer. [also shown as S6:E21]

On the sub-zero Canadian prairie, Royal Canadian Mounted Police discover a woman inside her hoarder home, a bloody ice-axe beside her. Her adult nephew lies frozen in the bed of his pick-up. Now, it's up to the Mounties to track down their killer. [also shown as S6:E20]

Devoted father and aspiring boat captain Tray Phelps takes his last breath, murdered just steps from his front door; with no immediate leads, it's up to Missouri investigators to find the murderous manipulator at the heart of a sordid family plot. [also shown as S6:E19]

Bookkeeper Barbara Iske fails to arrive on time at the Michigan home of her wealthy client; five hours later, she's found executed in the driveway of that same client; ultimately, police reveal that Barbara's the victim of a dark family conflict. [also shown as S6:E18]

In an affluent New York suburb, killers torture and beat millionaire Ben Novak in his hotel room; detectives soon discover that the businessman had many enemies, but one above all is the sadistic mastermind. [also shown as S6:E17]

On New Year's Eve in rural Pennsylvania, someone assaults and sets 23-year-old Ashley Kline on fire, killing her. The list of prime suspects includes her best friend, a jealous boyfriend, and a recently released prison pen-pal convicted of sexual assault. [also shown as S6:E16]

A gunman strikes down an Atlanta-area man in his SUV on the side of a motorway. Sheriff Investigators discover the victim is not well-liked among some in his inner-circle. But the killer eludes the law for 17 long years. [also shown as S6:E15]

A gunman kills volunteer police officer Laura Grillo in her suburban Dallas home. Investigators must link a bombshell accusation to a game-changing email with a diabolical mastermind who thinks he can outsmart the law. [also shown as S6:E14]

A killer stabs a beloved New Jersey woman 44 times in her home. Investigators have the culprit's DNA, but finding him will require an assist from the FBI, a media blitz and a random tip with details only the murderer would know. [also shown as S6:E9]

When the body of a single mother turns up in a snowbank outside Anchorage, Alaska, the evidence points to the victim's fugitive fiancé; the shocking murder of a second native Alaskan sparks investigators' fears that a serial killer is on the loose. [also shown as S6:E8]

After a public health nurse vanishes without a trace, Anchorage, Alaska, investigators get a major break from her terrified neighbor; the race is on to recover evidence before it disappears under Alaska's winter snow. [also shown as S6:E7]

The shooting of successful paediatric dentist Kendra Hatcher in the gated parking garage of her Dallas condo spurs detectives to unravel a twisted plot as they chase a fugitive who ends up on the FBI's most-wanted list.

A coworker finds Dr. Joseph Sonnier's body face down in the garage of his Texas home. Before long, the list of possible suspects includes the victim's girlfriend, a mysterious stalker, and a long list of jilted ex-lovers.

A Tennessee college student returns to campus to find her friend and roommate Heather Maples viciously strangled in her bed. The outgoing co-ed has many friends, but police fear that on August 7, 2015, one of those pals turns out to be her worst enemy.

In affluent Colleyville, Texas, a bloody home invasion leaves the housekeeper dead - but police soon discover she was the intended target all along. Little did the sweet grandmother know just how many people were impatiently waiting for her to die.

Early one May morning in 2012, a Kentucky pharmaceutical company employee stumbles upon the body of a close colleague. Someone has beaten this devoted wife and mother to death, and police must eliminate her coworkers as suspects, one by one.

A diligent art student lies stabbed to death in bed. The ferociousness of the crime makes little sense considering the quiet co-ed has no known enemies. However, police soon meet someone whose secret hatred for her reveals itself as a night of pure horror.

In Brooklyn's Hasidic community, Menachem Stark enjoys life as a respected businessman and father to seven children. In 2014, his wife calls police when he fails to return home, and a subsequent search leads to a burning dumpster that holds a dark secret.

A single woman hosts a dinner party on the same night she's mercilessly stabbed to death. At the scene, police notice her signature waist-length hair is cut short, leading them to suspect the killer not only knows the woman - but is obsessed with her.

High school Freshman Tina Faelz ditches detention and heads for home - but someone murders her along the way. Suspects are plentiful, including a known sex offender, but decades pass before two determined detectives finally deliver justice for Tina.

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.

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.

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.

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.

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

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 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.

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 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.

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 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.

A 42-year-old Russian woman living the American dream in Texas is savagely gunned down in her garage. As investigators work the case, the list of suspects includes her controlling ex-husband, her boyfriend, an obsessive admirer, and a generous mentor.

The murder of a beloved father days before Christmas shatters his family.

A former marine's death reveals a string of angry coworkers and irate exes.

A 30-year-old woman is reported missing by her concerned husband after she fails to report to work. When her abandoned car is found, traces of blood in the trunk indicate more than just a disappearance - it's clear she has been murdered.

A 27-year-old law student is reported missing, and when investigators later find human remains in the trash can behind her apartment, it's undeniable that the two are related. Police in Macon, Georgia, must act fast to catch a cold-blooded killer.

When a charming 33-year-old is gunned down outside his home, detectives must comb over every detail of his personal life, professional dealings, and extracurricular activities to figure out who could commit such a brutal crime, and why.

A car explosion outside a Tucson country club leaves a business tycoon dead. Detectives determine the killer detonated the homemade bomb at close range, and the list of suspects soon includes mobsters, defrauded investors, and the victim's ex-wife.

A young Iowa man is shot dead while he sleeps peacefully next to his fiancée. Investigators wonder how she remained unharmed, and suspicion quickly swirls around her and two of her ex-boyfriends.

Snowplow King Randy Scheffield is found shot dead in his bed by his wife on the first snowy day of the season, and Ohio detectives look into Randy's business to establish a motive.

When newlyweds Joe and Olga Connell are gunned down outside their Wilmington, Del., home, police investigate a sibling rivalry, a business partnership plagued by drugs, and an outlaw motorcycle gang.

Two young girls arrive home from school 10 days before Christmas and find their father dead; police narrow the timeline of the murder down to an eight-minute window before the girls walked in the door

When a small-town Michigan couple is gunned down in their own home, footprints in the snow and loose lips will lead police to their killer.

When the badly decomposed body of Margarita Scott is found in the backseat of her estranged husband's missing SUV, investigators must interview everyone close to her to retrace her final steps.