A sleepy Pennsylvania town is rocked when a popular dentist is discovered lying in a pool of blood. Police uncover few clues but plenty of rumors.

A mother, Debi Whitlock, is found brutally murdered in her California home. Police discover that Debi's life was anything but peaceful. For six years, Debi's mother leads a media campaign that is key to finding her daughter's killer.

In Boston, a white couple is carjacked and shot. The husband calls 911 and describes their assailant as an African-American male. Racial tensions are high as police pin down two suspects, but there could be a third suspect with a motive for murder.

Parceled into a series of plastic bags, the dismembered body of Karyn Slover is found floating in an Illinois lake. An autopsy reveals she also suffered multiple gunshot wounds to the head.

A photographer from Switzerland is brutally murdered in his Los Angeles home. Blood has dripped from the ceiling, glass is everywhere, and the body of 37-year-old Roland Kuster lies face down on the floor. Police hope forensic science can crack the case.

A serial killer is on the loose in the college town of Gainesville, Florida. And although police close in on their prime suspect, they fail to establish a forensic link and the case goes cold.

Spring Hill, Florida, is rocked by a series of violent crimes. All signs point to a serial killer with a taste for elderly women and fire, but police and the FBI find little evidence to solve the case.

A British exchange student is murdered in the Italian university town of Perugia. With her throat slashed, Meredith Kercher's half-naked body is found in her bedroom. The case makes global headlines, and police are under pressure to find a culprit fast.

In Michigan, a 15-year-old is abducted and strangled, her naked body dumped in a nearby orchard. Police line up a slew of suspects, but the case goes cold. But ten years later, a grand jury dusts off the case, and finds the truth has been there all along.

A pretty Brooklyn college student disappears after a night out, and police are convinced she's been abducted. Two days later, her remains are found in an empty home. Police assemble a list of possible culprits including an ex-boyfriend named Psycho.

Near Chicago, seven fast food workers are gunned down and their bodies left in the restaurant's walk-in freezer. With the community's residents reeling, and the media clamoring for answers, police struggle to piece together the deadly puzzle.

When the body of a San Diego man is found in his burned car, investigators begin a bizarre murder mystery. Many people are possible suspects, but the case goes cold. A woman makes a confession, and a tale of jealousy and cold-blooded murder is revealed.

A McDonald's restaurant manager is murdered in a small Tennessee town and the police force goes into overdrive. But with a big list of suspects investigators are baffled and the case goes cold. Two years later, a tip brings them to Delma Ramsey's killers.