In 1971, John List left a note with the bodies of his mother, wife, and three children in his mansion ballroom, funeral organ music blaring from a central sound system, and disappeared. Eighteen years later, all detectives had to work from is an outdated photograph of List. In 1989, the popular television series America's Most Wanted commissioned an age-scaled bust of List to aid viewers in identifying the confessed murderer. Dr. Frank Bender, nationally-recognized artist and sculptor, worked with forensic psychologist Richard Walter to develop a profile of the aging List.

In 1992, in a rural Canadian community, Dr. John Schneeberger is accused of sedating and sexually assaulting two of his female patients. DNA tests show him to be innocent, but the women persist with their claims; 7 years later, a private investigation leads to a surprising discovery.

In 1989, the bodies of Joan Rogers and her two teenage daughters were found floating in Tampa Bay. The water washed away any evidence, but police hoped a handwritten note found in the victims' car would lead to the killer, so they posted huge copies of the note on five highway billboards.

Haunted by the disappearance of her mother some twenty years earlier, a young woman undertook an investigation of her own. Her mother's diary was in the now cold case file; there, in her mother's own handwriting, she discovered a dark family secret, which might have been the reason her mother vanished.

A young man was killed in a mysterious car crash, but the evidence at the scene led investigators to believe it was not an accident. Forensic science revealed what really happened, and the truth devastated three families.

In 2003, Tiffany Rowell and three of her friends were brutally murdered in their affluent Clear Lake, TX, neighborhood and the crime scene yielded little evidence. The next-door neighbors had seen two young people dressed in black walking nearby and their descriptions were used to create composite drawings, which become a key element in solving the crime.

Two people in Seattle, Washington died after taking an over-the-counter pain reliever; lab analysis of the pills showed they were tainted with a lethal concentration of cyanide. The investigation which followed led police to a suspect with a motive for murder and a callous disregard for others.

When a decomposed body is discovered inside a barrel, police immediately suspect foul play. But the body had been placed there 30 years earlier. One of the few clues was an address book found along with the body but years of moisture had washed away the ink. Scientists desperately searched for a way to unlock the secrets of that address book.

In 1994, a human skull found in an Ohio pond uncovers a ghastly crime. Markings on the skull indicate that the victim had been stabbed many times and that the teeth had been removed with needle-nose pliers in an attempt to keep the victim's identity a secret. Forensic scientists use DNA matches to indentify the skull.

The use of the computers by law enforcement is detailed in this look at a series of crimes in St. Louis that stumped the local police and the FBI. (also marked as S7:E44)

Authorities are able to apprehend a kidnapper because he allowed his victim, 17-year-old Shari Smith, to write a will on a telltale pad of paper. [also marked as S7:E52]

The body of a young California co-ed was found under an isolated ramp of the Interstate, and San Diego police had no idea who would want this girl dead. But their questions would be answered when they discovered a tiny, unique fiber on the victim's clothing, which led them straight to the most unlikely of killers.

In 2005, David Castor suffered a slow, agonizing death over a period of days. His wife Stacey maintained it was suicide, even though it was done with antifreeze. Police were skeptical, especially when they learned Stacey's first husband Michael Wallace died when he was only 38 years old and she refused to consent to an autopsy.

The first case to use DNA evidence is detailed. In 1983 Leicester, England, police were stymied by a rape/murder of a 15-year-old girl; three years later, faced with a similar crime, they turned to Dr. Alec Jeffreys, a molecular biologist with a revolutionary approach to solving the case.

The year was 1984, and a serial killer was on the loose in Florida. Eight women had been found dead. At each crime scene, investigators found tiny red fibers, fibers they hoped would lead them to the killer.

Creating a “profile” of a serial killer is part science and part intuition. The science involves studying criminals who have committed similar crimes, to see what characteristics they have in common. In a search for the killer of two teenagers in Texas, a behavioral profile led to a possible suspect - and hard science proved the profile was correct; it shows a behavioral study on how most serial killers also have a history of abusing animals.

In Dripping Springs, TX, March 1999, a 3-year-old boy develops serious respiratory problems and then his father later shows signs of early Alzheimer's disease. A chance encounter with a stranger kicks off an investigation into the cause. [also marked as S7:E19]

In 1984, California firefighters had battled ten arson fires in three weeks. When cigarettes and a scrap of paper connected the southern California fires to several fires further north, the hunt was on for a dangerous pyromaniac. Investigators finally found a fingerprint, and it pointed to a most unlikely suspect.

A two-man shrimp boat sank when a fast-moving, violent storm struck the Louisiana coast. The captain drowned, and the deckhand was rescued fourteen hours later. He told the Coast Guard that the captain's foot had become entangled in the fishing nets; they tried frantically to free him, but they failed. The deckhand was considered a hero until the captain's body was found. Eventually, the public discovers that he was coerced into confessing to the captain's murder.

In 1994, 19-year-old college co-ed Shannon Melendi disappeared while at Emory University in Atlanta. For ten years, her disappearance of remained a mystery, until new scientific testing cast a different light on someone who had been a suspect from the beginning.

A millionaire and his family were executed in their own home. For three years, the murders went unsolved and then a 30-year-old box of ammunition and some fluorescent fibers revealed the ultimate betrayal.

In 2003, Rebecca Barney and her soon-to-be ex-husband Fred were found shot to death in their Tulsa, OK, home, which had been set on fire. After the fire was extinguished, Kenneth Maxwell, who was the man who had called 911 to report the fire, was also found shot dead in his car. Only the computer had been taken from the Barney home and with it, seemingly the means to identify the killer.

In 2003, Kathy Lorick was raped and murdered on a Concord, California jogging trail in the middle of the day while talking to her husband on her mobile phone. The leads from Kathy's cell phone records and search dogs go nowhere. Nine days later, a witness tells police about a chance encounter.

The case of missing stewardess Helle Craft is recounted. Although her body was never recovered, police used forensic evidence to charge her husband with murder. It became the first murder conviction without a body in Connecticut.

The flu-like symptoms of a mother and her children proved to be indicative something much more serious: thallium poisoning. Investigators had to find the source of the poison... and when the mother died, to determine if the exposure was accidental, or if they also needed to find a killer.