When the head chef of a historic Philadelphia restaurant was found dead, investigators interviewed the usual suspects: family, friends and coworkers. As they sifted through the evidence, police uncovered a chilling tale of debt and deceit.

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.

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 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.