Investigating an execution-style murder in a luxurious Miami suburb, detectives uncover a thriving law practice that made plenty of enemies, a business partner caught in a lie, and a troubled son with a lifelong grudge.

A Pennsylvania Sunday school teacher is executed in a sniper-style attack.

A young woman is found floating in a river off Merritt Island, east of Orlando, Florida. And as the circumstantial evidence piles up, the shifting story of one suspects' timeline ultimately becomes the smoking gun.

Fifteen-year-old twin girls make a horrific after-school discovery when they come home to find their mother floating dead in the bathtub. Their compelling testimony leads the investigation, but the hair-raising truth lies hidden in the details.

Searching for a dismembered New Hampshire woman's killer, police identify a series of potential suspects including a mysterious drifter named Razor. But the truth lies in a missing persons report, and a one-eyed teddy bear.

A Jacksonville firefighter discovers his wife's lifeless body in the bedroom of their home. His confession of infidelity initially makes him the prime suspect. But it's a stolen car caught on CCTV that ultimately leads investigators to the killer.

A double homicide in New York City soon becomes a media circus when investigators reveal the two victims led a secret life; as the list of suspects grows, it's a call from the victims' home that may provide the only link to the killer.

A tight-knit Georgia community is in shock when a 41-year-old woman is bludgeoned to death in her own home. As detectives look to piece together her final hours, a story from behind bars reveals the shocking motive for murder.

In an affluent Atlanta suburb, a young boy is stabbed 18 times when he returns home from school, and his mother's lifeless body is discovered in her bedroom; a neighbor's chilling story points police toward a psychopath.

When an 18-year-old Staten Island woman is murdered in her home, the media turns her secret into a front-page scandal. But a meticulously constructed timeline allows detectives to close in on their number one suspect.

The investigation into a Florida woman's murder takes a bizarre turn when an out-of-state tip about a homicidal hitchhiker. But the smoking gun comes via a local pawnshop, revealing a killer who lurks dangerously close to home.

Georgia detectives investigate the timeline of a family involved in a triple shooting find motive in both their failing business and a local addict with a grudge. But the discovery of a hidden key ultimately unlocks the secret to the killer's identity.

Confessed fraudster Andrew Kissel is found stabbed to death in the basement of his rented Greenwich, Connecticut home. And in order to find the killer detectives must unravel every detail of his last 24 hours.

When Diane Holik's body is discovered in her Texas home, detectives are faced with one of the most pristine crime scenes they've ever encountered; they unearth multiple suspects, but only the victim's reconstructed timeline can identify the killer.

When a Louisiana man is shot in his sleep, detectives uncover details of his extracurricular love life and a death policy that promised to pay out, even in the event of his murder.

Amid rumors of buried treasure at a Louisiana pet cemetery, the property's reclusive owner is found wrapped in heavy chains at the bottom of a river. Somebody wanted her to disappear, but it will take over 20 years before police can find her killer.

After Genore Guillory is brutally murdered in her own home, investigators look at several suspects on the woman's final 24-hour timeline; unable to pin anyone down, the case goes cold, until a witness comes forward with the inside story.

When firefighters in Arlington, Texas extinguish the flames of an apartment fire, they discover the charred remains of 19-year-old Missy Grubaugh. Several of her restaurant coworkers soon come under scrutiny.

When a nursing student is shot dead outside a Houston community college, the search is on for a brazen shooter in a red car. Detectives retrace the last 24 hours of the victim's life, and unearth a number of potential suspects.

The body of a 16-year-old high school cheerleader is found floating in a river bordering Texas and Oklahoma; the police investigation unearths several promising suspects, then a break points to a killer already in their midst.

Popular newlyweds Rick and Gail Brink are shot execution-style in their Michigan home. But it will take 25 years before investigators uncover a flaw in the timeline that convinces them of the killer's guilt.

A man comes home to find his fiancée dead in the bedroom of their new home; the discovery of infidelity soon puts him firmly in the hot seat; as investigators piece together the victim's final 24 hours, they uncover a sinister plot.

In rural Michigan, 34-year-old Deborah Boothby is run over on the highway, and for nine years the case goes unsolved. That is, until a team of detectives review the evidence and the hit-and-run cold case becomes a murder investigation.

Sixteen-year-old Theresa Burns is brutally murdered in her family's Indiana home; though investigators believe they've found the murder weapon, it will take a quarter of a century before they close in on the killer.

When a woman is murdered in her Alabama home, investigators receive a lead pointing to a high-profile suspect, but it will take a decade before their circumstantial murder case has enough substance to go to trial.

A successful vacuum salesman is gunned down outside his Indiana office; as detectives untangle the victims' final 24 hours, all the clues point to a hired hit.

Detectives hunt for the murderer of a businessman who was shot dead in his bed two days after Christmas. They try to find the killer by looking at the last 24 hours of the victim's life.

A Portland factory worker finds his missing SUV two months after it went missing, with the body of his estranged wife in the back seat.

Katrina Smith is reported missing in a close-knit community near Chicago, and detectives are faced with three prime suspects when her body is found in a river.

When a small-town Michigan couple is slaughtered in their own home, the only hard evidence is a trail of footprints in the snow, and the case soon goes cold. That is, until a random tip leads investigators right back to square one.

Police investigate when the body of a 24-year-old college student is found dumped in a Brooklyn neighbourhood.

Just days before Christmas, an Ohio man is gunned down in his home. And as detectives narrow the timeline to a mere eight-minute window, they need to determine the identity of a mystery man with a sinister motive.

Florida detectives suspect a missing 49-year-old hotelier named Sabine Musil Buehler has been murdered. And in the no-body homicide, narrowing down the timeline proves more critical than ever

As detectives investigate the brutal murder of a Tampa bartender, it’s the victim’s own handwritten notes that break the case wide open, and the team soon closes in on a manipulative predator who cleverly outsourced his cold-blooded ambitions.

A media firestorm erupts in Georgia when a law student's dismembered torso is discovered in a dustbin outside her home.

A 63-year-old retired Air Force captain is doused with sulfuric acid in the parking lot of a Florida supermarket. Eyewitnesses describe a shirtless attacker in his 30s, and investigators eventually uncover a deadly neighborhood feud and a manipulative mastermind with a barbaric plan.

An exploration of how the shooter of Desiree Sunford, a teacher, was brought to justice and how he nearly evaded the law altogether.

When an Iowa man is gunned down in his sleep, suspicions swirl around his fiancée. But the list of suspects soon expands to include her two ex-boyfriends and a mysterious case of stolen identity.

In Texas, the body of Dr. Joseph Sonnier is discovered face down in the garage of his home.

Kendra Hatcher, a renowned pediatric dentist, is shot to death in the enclosed parking lot of her Dallas apartment.

A successful physician with a TV career ahead of her is bludgeoned to death in her Florida home.

A mysterious 911 call alerts the police to the murder of a Harvard graduate.

In Florida, a cell phone could help solve a case involving the torture and murder of a man.

A suitcase found in Connecticut contains a macabre and tragic discovery.

In Anchorage, a public health nurse goes missing, and the investigators get help from a terrified neighbor.

In Alaska, police fear a serial killer is on the loose, murdering native women.

In New Jersey, a woman is violently stabbed in her house.

Niagara Falls investigators find a serial monogamist slaughtered to death.

An enraged killer attacks 26-year-old Alexandra Ducsay, an aspiring artist with a big heart and a blossoming career.

Terri Brooks, assistant manager of a Pennsylvania restaurant, is brutally murdered after being robbed.

A gunman shoots William Walker, lieutenant of the Cleveland Fire Department, in his own driveway.