Now it's not only a fingerprint which can link a killer to a crime; a shoe print can be just as telling. Armed with little else, police hoped the shoe impressions found at a Lansing, MI crime scene would put their investigation of Audrey Nichols' murder back on track.

A woman was found dead on the bedroom floor of her apartment. The crime scene yielded little of value, and investigators wondered if they would find enough evidence to make a case, much less catch a killer. But a bloodstained sheet and a breakthrough forensic technique enabled them to identify the murderer, and convince the jury of his guilt.

In 1993, 82-year-old Kathryn Bishop was found dead in her Pennsylvania home. The evidence at the scene indicated that the perpetrator had been running out of the house, not breaking into it. Tiny clues on the victim's body would tell police what happened that night, and who was responsible.

A wealthy man and his wife were attacked by three men outside their luxurious Louisiana home. He was shot dead and she was forced to open their hidden safe. The woman could not describe the men because they wore masks. To solve the case, police would have to find out who knew about the concealed safe, and who would benefit from the crime.

A lifelong resident of the tiny town of Lefroy, Tasmania was murdered outside his own home. Robbery appeared to be the motive, but with no suspects, the investigation came to a halt. Then the victim's autopsy turned the investigation into a landmark forensics case: the device intended to save his life proved to be the only witness to his death.

When a wealthy socialite died after falling down the stairs, the eye witnesses said one thing and the evidence seemed to indicate another. To find out what really happened, investigators turned to forensic science, a physicist and an expert in accident reconstruction.

It's usually easy to determine how a criminal entered the crime scene. But in this case, it was far from clear. It looked like the killer vanished into thin air...and perhaps he had.

When a young fireman died from what appeared to be serious but undiagnosed heart disease, his family and friends were devastated but they had no proof of foul play. Then they learned that, six years earlier in a nearby town, a young police officer died in the same way. The men had one thing in common: at the time of their deaths, they were married to the same woman.

How unlucky could one man be? His wife had taken her own life, and his college sweetheart had killed herself in much the same fashion fourteen years earlier. Investigators had to determine if this was a bizarre coincidence, or an attempt to get away with murder... twice.

A woman was brutally murdered in her home, and the only witnesses to the crime were the family dogs. An expert in canine behavior was convinced the killer knew both the victim and the animals, and he was determined find out exactly what the dogs had seen.

After the suspect was convicted of arson and murder, he steadfastly maintained he did not commit the crimes, but he was sentenced to a minimum of 25 years in prison. He had no money, no lawyer and only a fifth grade education, but he never gave up. He turned to the law books in the prison library and television programs about forensic science, and set out to prove his innocence. [also marked as S12:25]