In 1997, Kelly Eckart's car was found, with her belongings still in it, after she worked a late shift in Franklin, Indiana. Days later, her body was found in an isolated ravine.
In the 1990s, the media dubbed Richard Rogers the "Last Call Killer" because he targeted men in gay bars.
A security guard disappeared from his post without a trace his remains were found a year later in a remote camp site.
The victim was a self-made man who never minced words. Perhaps he was murdered by a disgruntled client.
The wife of a respected police officer was murdered in her own home. The crime went unsolved for more than a decade, until a newly formed cold case unit took a fresh look at the evidence.
Police get a clue about a couple who disappeared on Memorial Day weekend during an in-progress robbery.
In 2004, Rebecca Barney and her soon-to-be ex-husband Fred were found shot to death in their Tulsa, Oklahoma, home, which had been set on fire.
When two women went missing and were later found brutally murdered, police wondered if they were victims of a hate crime.
The victim was well liked and successful, which made the brutality of the crime even harder to understand.
They thought the fire would cover their crime. But one tiny clue led to a trio of killers behind bars.
The victim had ingested a massive amount of cyanide. An unlikely clue - a flaw on a mailing envelope - exposed a murderer who was willing to kill innocent people.
A murder trail turned cold, until police got a call from a woman whose husband, Gerald Powers, had a criminal past and a fondness for Chevy Berettas.
Christina Sanoubane was murdered in her Cedar Rapids apartment after moving away from her abusive boyfriend.
There was no clear reason for a young, healthy college student to be dead. But when the coroner discovered a tiny clue during the autopsy, investigators were able to uncover a mystery.
In 1986, Gary Dale Larson was stabbed to death in his Edmond, Oklahoma home and then the killer sexually assaulted Larson's girlfriend Janet Haynes.
A serial killer was on the loose and police had to find him before he struck again. Their most promising lead was an unusual one: a bloody fingerprint on the body of one of the victims.
In 2003, St. Cloud teenager Jason MacLennan returned home after a night out with friends and discovered his father Ken's body lying in a pool of blood.
In 2000, Judy Southern arrived home from work and was shot by a gunman waiting within. Her husband Allen arrived shortly afterwards, called 911 to report his wife had been shot.
A young woman attends evening church services... then disappears. When her abandoned car is found, the tank is empty and a gas can she kept in her trunk for emergencies is missing.
In 1993, young mother Tammy Tatum was sexually assaulted and murdered in her Longmont, Colorado apartment.