Emergency personnel were called to the home of Richard Alfredo, who was slumped over, dead of an apparent heart attack. No one thought foul play was a possibility until police looked into the odd behavior of his girlfriend Christina Martin. Controversy surrounded the case for almost a decade, which pitted competing teams of toxicologists against each other. Originally aired as Season 8, Episode 1.

In this classic episode of Forensic Files, the longest running true crime series in television history, the sense of security in Waseca, Minnesota shatters when 12-year-old Cally Jo Larson is found dead in her home. Despite an exhaustive investigation, only a string of burglaries, which lead police to a cache of stolen goods, brings a killer to justice. Originally aired as Season 8, Episode 2.

In 1962, the people of the small town of Hanford, California lost their sense of peace when one of their own, 15 year-old Marlene Miller, was murdered. It would take 24 years and countless retrials before forensic scientists discovered the microscopic evidence that brought the killer to justice. Originally aired as Season 8, Episode 3.

A mother of two disappears after a shopping trip. Her body is found a month later. Witnesses saw the victim being forced into a car by an unknown person. Police learn that the car had been rented, but the signature on the rental agreement does not match that of their number one suspect. A forensic handwriting expert points to the murderer. Originally aired as Season 8, Episode 4.

The day before she was scheduled to testify against the man accused of robbing her, a woman is shot to death in her store. Police ask a physics professor to examine the would-be defendant's alibi: a time-stamped videotape.

In 1993, thieves were robbing and killing tourists in Florida, making worldwide headlines. One victim fought back, suffering a bite mark that became key evidence against a determined suspect - who ran into a even more determined detective.

Due to a bite mark, an Arizona man is convicted and sentenced to death for the 1991 murder of a bartender. However, he fights to prove his innocence.

A woman's death in Pennsylvania triggers a homicide investigation into another woman's death in North Carolina. The similarities in the two cases are shocking, and medical examiners must determine if the suspect's story about accidental drowning is all wet. Orginally aired as Season 8 Episode 8.

A nurse has a variety of flu-like symptoms. None of her doctors are able to find the cause, until she visits the gynecologist for a routine check-up. Then she learns it's something far worse than the flu. She is HIV-positive. Science determines not only how she had been infected, but also by whom. They will discover that it wasn't an accident. Orginially aired as Season 8 Episode 9.

Time of death becomes pivotal when a pregnant woman is found murdered in her Connecticut home. The couple's adventurous sex life comes into play, and a striking similarity between the woman's death and an HBO movie gives forensic examiners the clues they need to thaw out the alibi of a cold-blooded killer.

In Peoria, Illinois, police discover a footprint that could identify an intruder who killed a young man and attacked two teenage girls.

A man is found shot to death in his home. Determining time of death becomes fatally important, and in order to do so, investigators need to know when the victim ate his last meal. An endocrinologist, a forensic botanist and a short-order cook try to solve their mystery. Orginially aired as Season 8 Episode 12.

Neighbers do not hear the gunshots when a union official is killed in his home.

A man is declared a hero after claiming that he shot an intruder who killed his wife, but four years later, newly acquired forensic evidence leads authorities to reexamine his story.

When a police officers wife is found dead from an apparent shotgun blast at close range investigators and peers of the officer are quick to make judgment in the case. Were the original conclusions and theories about the wife's mysterious deaths accurate? And would the suspicions for and against the officer righteous? Investigators and forensic professionals unveil the truth about who pulled the trigger ending this young woman's life one tragic day.

William "Blaine" Hodges, a U.S. Postal Service employee, is convicted of embezzlement in Roanoke, Virginia. But before he can report to prison, the Hodges family home is found on fire and the entire family is found dead inside. Mom, Teresa Hodges, has been strangled, and Dad, Blaine Hodges, and his daughters Winter and Anah have all been shot in the head. Although the crime scene appears to be a murder-suicide, the coroner rules that out quickly: Blaine Hodges was not only dead before the fire was set, but his body had already started to decay. As the police interview...

The double homicide of a gay couple leads investigators into the twisted world of White Supremacists. Shell casings, paint chips and an analysis of glass shards help authorities link their prime suspects to a string of hate crimes in California U.S.A.

With no forensic evidence inside a murder scene, investigators are left puzzled. But they suspected that the victim's dog had witnessed the crime. If she had, forensic scientists would have to find some way to know what the dog had seen. Originally aired as Season 8, Episode 18.

A killer ends the life of a young TV news producer using a knife from her own kitchen. Witnesses see a shirtless man with a tattoo on his chest running from her apartment, but the truest witness proves to be the killer's own blood.

A homicide detective murders his corrections officer wife, staging the scene to make it look as if she shot herself in the head by accident.

For years, a woman suffered from what appeared to be the unpleasant side effects of lithium, a drug prescribed to treat bipolar disorder. Her search for help led her to severals doctors and hospitals and resulted in a 4000-page medical file. When she died, investigators had to determine if her death was caused by natural causes, suicide or murder. Originally aired as Season 8, Episode 21.

A woman is found dead in a ravine near a jogging path. Significant crime scene evidence had been washed away by a series of thunderstorms. Twice, the trail turned cold. Then, almost twenty years later, an old hat and a chip of stainless steel no longer than a fingernail would finally bring the killer to justice. Originally aired as Season 8, Episode 22.

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. Her body was discovered 10 days later; she'd been shot twice at close range, and sexually assaulted. An eyewitness led police to a suspect and trace evidence found at the crime scene. Originally aired as Season 8, Episode 23.

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. It would take fifteen years, and the remarkable advances in forensic science and DNA testing which occurred during that time, to enable police to nail the killer.

From 1990 to 1993 a killer terrorized New York murdering 8 random people. Investigators begin finding with each new victim a strange pattern began to immerge. Each victim found at different locations and appeared to be unrelated victims were being killed each month representing the astrological sign of the new victims. With little evidence and no apparent connection between the victims the investigators were stumped as the city began to fear the unknown self proclaimed zodiac killer. Investigators needed a break and confident this suspect was not the same one who ...

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. Originally aired as Season 8, Episode 26.

Kathleen Lipscomb's body was found on a deserted street outside of San Antonio. Months passed, then years, and the crime went cold. Then Kathleen's family hired a private investigator who discovered a diary among her personal effects. Two of the diary entries helped police to piece together what had happened to Kathleen Lipscomb, and why. Originally aired as Season 8, Episode 27.

A retired police officer is found fatally shot in his bed, the apparent victim of a suicide. But evidence at the crime scene, along with forensic textbooks and a bank surveillance tape, prove it was murder.

A fire guts guts an apartment while its tenants are out of town, and the aftermath includes the corpses of two young women, neither of whom died in the fire. In fact, one died a day before the other.

Two men called police to report the same murder. Apparently, neither one knew that the other had called and the investigation uncovered even more unusual circumstances. But a few small seeds and a discarded candy wrapper will ultimately tell a story of revenge.

The body of a rich businessman was found in his rental car. Teeth and bone fragments were all that remained of the body; miraculously, an engraved wristwatch and medic alert bracelet had survived the inferno. When the victim's wife filed a claim for $7 million worth of life insurance, investigators sought the help of a renowned forensic anthropologist.

When a pipe bomb ripped through a rural home, killing a young man and seriously injuring his mother, police had no idea who was responsible. A lot number on a 9-volt battery and the remnants of a mailing label found on a computer's hard drive enabled investigators to determine who sent the bomb, and why. Originally aired as Season 8, Episode 32.

No one in a quiet residential community saw or heard anything unusual the day one of their neighbors was brutally murdered. Fingerprints found at the crime scene and surveillance video from a security camera helped investigators to apprehend the presumed killer within twelve hours - even though he'd already left the state and was on a bus, headed for New York City.

A Michigan junk yard owner is killed and the police can't find any evidence. It is only when computer experts examine two hard drives that the killers are eventually traced and an unusual story of sex and crime is uncovered.

A drive-by shooting leaves one man dead and another seriously wounded. Cell phone calls and shell casings point to a suspect, but authorities are unable to place him at the crime scene. When a forensic geologist compared soil from the crime scene with soil found in the wheel wells of the suspect's car, he proved that dirt is anything but dumb. Originally aired as Season 8, Episode 35.

In 1963, Australian teenager John Button is accused of running down his girlfriend on the roadway after a fight. After a brutal police interrogation he confesses, than recants. He is tried and convicted of manslaughter, sentenced to a primitive Victorian-era prison. He regains his physical freedom, but is branded a guilty man. Almost forty years later, a writer uncovers evidence that another man, a known serial killer, might really be responsible. In fact, he had confessed. An accident reconstruction expert tracks down antique cars to re-create the accident, and clear...

A high school gym teacher mysteriously leaves town without saying goodbye to anyone. He later sends letters to explain why. But a closer forensic look at those letters and a microscopic piece of tissue gives investigators an entirely different explanation for where he went and why. Originally aired as Season 8, Episode 37.

Detectives try to discover the cause of a Palestinian daughter's death in America. Did she provoke her parents and attack them or did her parents commit an honor killing?

A mysterious computer crash pushes a thriving manufacturing company to the brink of collapse, jeopardizing the jobs of hundreds of employees. There is no apparent cause and no obvious clues. Forensic investigators must determine if the crash was the result of a computer defect, human error, or sabotage. Originally aired as Season 8, Episode 39.

Investigating a 1983 vehicle crash between law enforcement officers on the occasion of a visit from the Queen of England.

In 1993, the Amtrak Railroad experienced the deadliest train crash in United States history, when the Sunset Limited derailed while crossing Alabama's Big Bayou Canot bridge. Forty-seven passengers and crew were killed; scores more were injured. The clues to the cause of the crash lay etched in twisted steel and buried in the mud of the Big Bayou Canot. Originally aired as Season 8 Episode 41

A fire erupted in the Kings Cross Underground Station in London, killing 31 people and injuring dozens more. Arson investigators were able to pinpoint the cause of the fire, but it would take state-of-the-art computer technology and experts in the field of fluid dynamics to explain why it became a deadly inferno.