A man died in his home after a long history of heart disease. It was assumed that this was the cause of his death. A few weeks after the funeral, rumors surfaced that the death was no accident.

In 1999, a 12-year-old was found murdered in her home and it changed the feeling of security residents had in the small town of Waseca, Minnesota. Despite a meticulous search of the home and an exhaustive investigation, police had no suspects.

In 1962, the people of the small town of Hanford, CA lost their sense of peace when one of their own, 15-year-old Marlene Miller, was murdered. Booker T. Hillery was convicted and after countless appeals, Hillery received a re-trial in 1983. Forensic scientists had to use new knowledge of microscopic evidence to be able to place Hillery at the scene.

A mother of two vanishes after a shopping trip. Her body is discovered a month later. Witnesses say they saw the victim being forced into a car by an unknown person.

A woman is shot to death in her store just one day before she is to testify against the man accused of robbing her. The robber becomes the prime suspect, but he has a solid alibi: a time-stamped videotape of his activities on the day of the murder.

In 1993, the state of Florida was known for more than just Disney World. Worldwide attention focused on a rash of robberies which targeted tourists. Some vacationers were killed in these attacks, but some fought and survived, despite severe injuries.

At a murder scene, investigators find a shoe-print, several foreign hairs, and unknown fingerprints. But they believe the most telling piece of evidence is the bite mark on the victim's chest.

A woman's death in Pennsylvania triggers a homicide investigation into another woman's death in North Carolina. The similarities in the cases were striking, and examiners must determine if the suspect's story about accidental drowning is all wet.

A 34-year-old nurse experiences a variety of flu-like symptoms. None of her doctors are able to discover the cause, until she visits the gynecologist for a routine check-up. Then she learns it's something far worse than the flu.

Time of death becomes pivotal after a pregnant woman is found murdered in her air-conditioned bedroom. A striking similarity between her death and an HBO movie gives examiners the clues they need to thaw out the alibi of a cold-blooded killer.

Police were puzzled by an obscure print found at a crime scene where one man had been killed and two teenage girls were seriously injured. Neither of the girls could identify their attacker. But one simple clue helped track the footsteps of a killer.

A man is found dead in his home, and his ex-wife has a perfect alibi. To determine time of death, investigators need to know when the victim ate his last meal. An endocrinologist, a forensic botanist, and a short-order cook answer their question.

A union official is executed in his home not long after a strike by the union membership. Neither his wife nor anyone in the neighborhood heard any gunshots. It would take a forensic sound test, an electron microscope, and a nightgown to explain why.

A man tells police he shot an intruder who had attacked and murdered his wife. The husband paints a tragic picture and is dubbed a hero. Four years later, forensic evidence leads police to re-examine the motives of this so-called hero.

A police officer accused of killing his estranged wife insists she committed suicide. Investigators say it was murder – that it was physically impossible for the woman to have shot herself. The crime scene evidence is interpreted differently by the defense and prosecution, and the jury must decide if the victim's death was suicide or cold-blooded murder.

When Firefighters found an entire family dead, inside their home, it looked like a murder-suicide, but there were several inconsistent clues in the rubble. Could ballistics, a time card, and some secret audiotapes unravel the mystery?

Two men were murdered, while sleeping in their bed. One night later, an arson fire destroyed a family planning clinic. Investigators wondered, wherether some shards of glass, paintchips and a chicken feather, could link for what appeared to be, two separate crimes.

With no forensic evidence inside a murder scene, investigators were baffled. But they suspected that the victim's dog had witnessed the crime. If she had, forensic scientists would have to find a way to find out what the dog had seen.

A young TV news producer is raped and murdered in her apartment. Police identify two suspects, but both are cleared of any wrongdoing. The case stalls for more than a year, and then investigators turn to the Commonwealth of Virginia's DNA Databank.

Police are dispatched to the scene of a shooting, and discover the victim's husband is one of their own: a homicide detective who says his wife accidentally shot herself in the head. The detective maintains he called 911 immediately, but the evidence seems to indicate otherwise. [also marked as S8:E10]

For years, a woman suffered from what appeared to be the unpleasant side effects of lithium, a drug prescribed to treat bipolar disorder. When she died, investigators had to determine if her death was due to natural causes, suicide, or murder.

A woman is found dead in a ravine, but crucial crime scene evidence had been washed away by severe thunderstorms. Twice, the trail turned cold. Almost 20 years later, an old hat and a chip of stainless steel brought the killer to justice.

When an 11-year-old girl disappeared from a small town in a remote area of Alaska, investigators wondered if she'd been attacked by a bear or become lost in the dense woods. It turned out neither was true.

Just weeks before a witness is to testify against the man accused of sexually assaulting her, she is murdered in the front yard of her own home. Investigators immediately suspect her attacker, but they don't have enough evidence to prove his guilt.

For six years, a serial killer prowled the streets of New York City. He wrote letters to police and The New York Post, indicating he would kill twelve people, one for each astrological sign.

A healthy young man dies mysteriously in his sleep. There are no signs of trauma or injury, but toxicology tests reveal a lethal dose of lidocaine in his blood. Investigators find a suicide note, and presume he killed himself until a forensic linguist examines the note and determines that what the victim said is less important than how he said it.

In the summer of 1986, Kathleen Lipscomb's body was found on a deserted road outside of San Antonio. Months passed, then years, and the crime was never solved. Then Kathleen's family hired a private investigator, who discovered her diary.

A retired police officer is discovered in his bed, dead of a single gunshot wound to the head. His wife first says the motive was robbery; then she tells police he committed suicide. It would take careful examination of the evidence at the crime scene, the tape from a bank surveillance camera, and forensic textbooks found in the victim's home to write the final chapter of this real-life whodunit. [also marked as S8:E19]

A suspicious fire swept through an apartment killing two young women. The cause of the fire and the identity of the victims were unclear. But a closer look at the fire scene revealed something hidden in the ashes.

Two different men called police to report the same murder. Apparently, neither one knew that the other had called. The investigation uncovered even more unusual circumstances.