A fire leads investigators to re-examine an unusual death.

A young woman's naked body is discovered in a remote area leading forensic investigators on a search for clues to her identity and the identity of her killer.

When a Yale student mysteriously vanishes days before her wedding, investigators comb a secure research lab for clues.

An almost-perfect crime was discovered because of a suitcase.

A popular handy man in a New Hampshire town is found murdered and investigators follow forensic clues to a shocking conclusion.

A young mother is murdered in a crowded parking lot in broad daylight.

A mysterious murder in an upscale community is solved by cellphone forensics.

A serial killer terrorizes a small Texas town.

After the brutal slaying of a young couple on a road trip, the victims' families begin receiving disturbing letters.

The unexpected and strange death of a health conscious woman prompts an investigation.

After a young mom is found brutally murdered in her home, investigators find startling clues on her cellphone that could lead to her killer.

An amazing new forensic tool turns a cold case around.

A gruesome discovery in a small town church sends investigators on a search for a killer.

An insurance agent is shot execution style in his office in broad daylight, but the killer left no fingerprints and there was no murder weapon found at the scene… Then, investigators discover a critical clue invisible to the naked eye that cracks the case. (also marked as S1:E12)

A healthy, young mother mysteriously dies after a minor traffic accident triggering an investigation to find out what caused of her death.

Investigators search for clues after a body is discovered in a watery grave.

The murder of a young teacher’s aide leaves a hole in the heart of her small community in Agawam, MA. As the rumor-mill about suspects churned, the actual perpetrator slips further away. But, generations of investigators and a scientific breakthrough leads to a shocking end to a tragic case.

51-year-old father, and teacher, Bill Sparkman is found hanging naked from a tree with the letters “FED” scrawled on his chest. With barely any evidence to work with, investigators turn to these letters for answers… which leads to a surprising conclusion that no one saw coming.

A 20-year-old woman sets out on her bike and never returns; her body found just a few miles from her house in Snohomish County, Washington, with a gunshot wound to the head. Years go by without any hard evidence or leads, until a new generation of investigators and modern technology breaks the case.

A single mom looking for love vanishes without a trace. Foul play is tragically confirmed when a large pickup truck toolbox opens to her body stuffed inside. Homicide detectives investigate men she matched on dating sites, another man she met at work, and finally, a lover with a secret and violent past. Can forensic evidence connect the dots and lead to justice under the law?

In 1982, 37-year-old, Navy lieutenant Lee Hartley is murdered while deployed out to sea. Cause of death? Arsenic poisoning. Investigators discover lee had more than his fair share of enemies aboard the ship. But it takes years before investigators discover what really happened to Lee and who, ultimately, was behind this brutal murder.

A building manager finds the violated and lifeless body of a young woman in the bathtub of her first apartment. When questioned, an ex-con living downstairs lies to police. But the lies alone do not prove murder and the case goes cold. Then a new forensic tool examines the old evidence. Will science point to a hidden suspect and crack the case?

A murder victim’s final moments are caught on tape. The crime scene looks like a clear robbery-murder. Text evidence at first points to a jilted lover, but will his alibi check out? Now police identify a second suspect with a possible motive of deadly revenge. Forensic technology and DNA evidence combine in an attempt to make the case.

A mortally wounded woman crawls to call 911. Her husband who wants a divorce she will not give him, gets a hard look from police. But he says he has an airtight alibi for the exact time of the murder. The intricate forensic science of ballistics is brought to bear to and draws s a direct connection to an unexpected conclusion.

A deeply religious librarian, wife and mother named Gail Fulton is shot execution style in the quiet suburbs of Michigan. Surveillance video reveals it was trio of killers that took her down. Is there more to Fulton’s background? Eventually, detectives get a break: a handwritten note. But will it provide enough clues to catch the mastermind behind this horrific killing?

In 1990, three sex workers are brutally murdered and left along the banks of the Spokane river. A serial killer was on the loose—and detectives had few clues. Animal hairs, fibers and a fingerprint were found, but for years the perp was never identified. More than 20 years later there’s a break in the case- and an arrest is finally made, but no one could have ever imagined who was behind this sinister crime.

He is a criminally charged sex offender and a murderer who attacks in a terrifying rage. This predator manages to evade capture for years, but he leaves a critical piece of evidence behind – his palm print. Detectives are determined to do whatever it takes to put a name and a face to the print.

An early morning house fire kills the only doctor in the small town of Iaeger, West Virginia. Who - or what – could have led to this? An arson investigation quickly leads to the arrest of Jason lively, the son of the doctor’s long-time nurse. But when Jason’s alleged accomplice walks free, the prosecutor is worried this might have been a miscarriage of justice.

On a brutally cold winter night in 1984, a young woman is found viciously murdered on the side of a rural Wisconsin driveway. The victim, Traci Hammerberg, had been out with friends for a night of drinking and partying. What happened? Detectives initially have plenty of suspects, but the investigation would remain unsolved. Until nearly three decades later, when forensics from an unrelated crime helps breaks the case.

A hearing impaired 77-year-old on a road trip is attacked by a thief and shot to death Why? Because the man cannot hear his assailant’s demands. Random murders are Among the hardest crimes to solve, but investigators are determined to bring this killer or killers to justice. Can advances in ballistics testing crack the case?

A massive explosion claims the life of a California farmhand. Authorities think it’s an accidental death, but analysis of debris shows it’s a bomb. Investigators have few suspects until they hear ominous rumors about a jealous rage.

When a beautiful college student is stabbed to death in her Knoxville apartment, suspicion immediately falls on her roommate. A bloody shoe print left by the killer exposes a murderer with no history of violence and no reason to kill.

Someone targets members of law enforcement in a peaceful Texas county. Numerous suspects emerge, and murders continue as detectives race against time. Finally, a single bullet casing uncovers the bizarre reason for which the killer wanted revenge.

An Illinois mother and her two young children are brutally murdered in their beds. Lurid threats are spray-painted all over the walls of the crime scene. Detectives discover death threats sent to the family, exposing an unlikely killer.

A young Texas teenager and her boyfriend are brutally attacked on Valentine’s Day; she is found dead while her boyfriend escapes. The case goes cold for nearly 50 years before a new forensic test exposes a family man with a dark secret.

Three Indiana construction workers are found shot dead at a work site. Detectives find few suspects, but have one key clue: one of the killers stepped in dog feces during the murders. If detectives can find his shoes, they’ve got their man.

A Texas ex-con resolves to live a clean life after his release from prison. When he’s later arrested and convicted for a bloody murder, he insists he’s innocent. From behind bars, he’s determined to use forensic science to prove his case.

An extremely successful California career woman keeps falling ill and doctors can’t determine why. When she dies, they still have no explanation, until they find a key figure in her life who has been lying about his past.

The body of a 24-year-old criminology student is found wrapped in a blanket alongside a desolate Road in Brooklyn New York. Police discover her killer.

When a 79-year-old woman is found shot to death in her home, investigators initially suspect her husband or a violent neighbor. Shell casings recovered at the scene and a high-tech database reveal an unlikely killer.

A young single mother is abducted from a gas station and later found stabbed to death near an oil field; detectives use shoe and tire impressions to weed out numerous suspects and find the killer.

When a 23-year-old Marine dies in his bedroom, doctors initially believe a heart attack is to blame; when arsenic is found in his organs, his wife is charged with murder; a sharp attorney and toxicological testing uncover the truth.

When an 18-year-old girl is abducted while talking on a payphone, forensic evidence found on her clothing points police in the direction of a suspect who shockingly confesses that he didn't act alone.

In the story of a Los Angeles kidnapping, ransom and murder ring, retired scientists use sonar equipment to locate victims at the bottom of a reservoir.

Patients at the VA hospital in Clarksburg, WV, keep dying after experiencing shockingly low blood sugar levels. An investigation into their deaths reveals an overnight nurse was injecting patients with lethal doses of insulin.

A 70-year-old retired veteran is found dead on his boat after a bad sea storm; detectives discover he was killed during an attempted robbery after winning $400 in keno.

A true-crime enthusiast may help crack a missing persons case in Ohio.

An upscale apparel store in Bethesda, Md., is the site of a gruesome scene when an employee is killed and her co-worker is battered and tied up, but surveillance video and blood evidence shed further light on the crime.

Eight days after she had disappeared on her way to a family ski trip, an 18-year-old young woman's partially nude body is found floating in a river in Wyoming, Years later, DNA technology uncovers dark secrets that led to her demise.

California police are baffled when an innocent man's DNA is found at the scene of a deadly home invasion, and authorities team with the man's defense attorney.

A young Colorado mother suddenly vanishes on Thanksgiving, but when police trace her cell phone, it leads them to a surprising character with an even more surprising story.

A young mother is found murdered in her home and there are two suspects with ample motive, but an unusual interview and security camera footage have investigators puzzled.

After the discovery of the brutal murder of an 18-year-old desk clerk of a beachfront condo, analysts use brand-new mitochondrial DNA technology to prove the killer's identity.

July Fourth weekend leads to a tragedy for a California family; to catch a killer, detectives utilize an unorthodox technique—analyzing bug fragments—to help put a murderer behind bars.

A Texas love triangle turns deadly, and it appears to be an open-and-shut case until technology tells the tale.

A 33-year-old West Virginia husband and father seemingly dies in an accidental house fire; a closer look at the scene reveals a more sinister case.

A family mourns the unexpected death of a beloved grandmother at Christmas, and while local police assure everyone that she was the victim of a tragic accident and that there is no foul play, some things about the scene don't add up.

When the 20-year-old clerk of an Atlanta-area smoke shop is gunned down during a robbery, investigators have only descriptions of the killers and the make of their getaway car; investigators use a videotaped confession to smoke out the killers.