The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events.

A volunteer police officer is shot dead in her suburban Dallas home.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life.

A predator sneaks in with a master key and strangles a young single mother.

A gunman strikes down an Atlanta man in his SUV on the side of a highway.

A bookkeeper takes her last breath on the driveway of a wealthy client.

Missouri detectives hunt for a murderous master manipulator.

A young Pennsylvania woman is brutally murdered on New Year's Eve.

On the sub-zero Canadian prairie, Royal Canadian Mounted Police discover a woman inside her hoarder home, a bloody ice-axe beside her. Her adult nephew lies frozen in the bed of his pick-up. Now, it's up to the Mounties to track down their killer.

When Florida invesigators find a retired Marine in his home—beaten, then slain by a shotgun blast—their suspect lists grows from his estranged son to a mystery woman he’d only just met, then to a possible serial killer.

After Santa Barbara Police find a PhD student shot dead on his doorstep, California investigators unravel a cold-blooded family plot that hinges on a single strand of DNA.

After Michigan detectives find a popular hairstylist stabbed to death, their suspects include the victim’s landlord, her married lover, and an aggressive ex-boyfriend. But it’s an unexpected call that ultimately leads police in the right direction.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events during this critical window.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events during this critical window.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events during this critical window.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events during this critical window.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events during this critical window.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events during this critical window.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events during this critical window.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events during this critical window.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events during this critical window.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events during this critical window.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events during this critical window.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events during this critical window.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events during this critical window.

This true-crime documentary series follows investigators as they piece together events during this critical window.

This true-crime documentary series follows investigators as they piece together events during this critical window.

This true-crime documentary series follows investigators as they piece together events during this critical window.

This true-crime documentary series follows investigators as they piece together events during this critical window.

This true-crime documentary series follows investigators as they piece together events during this critical window.

This true-crime documentary series follows investigators as they piece together events during this critical window.

This true-crime documentary series follows investigators as they piece together events during this critical window.

A church-going businessman is shot in his home by a masked intruder. As police investigate, they learn just how far the victim would go for success.

This true-crime documentary series follows investigators as they piece together events during this critical window.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events during this critical window.

Detectives investigate the death of a divorced mother of five, brutally strangled in her own home. They scour through her dating history to try and find clues that could lead to her killer.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events during this critical window.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events.

The key to solving the toughest homicides lies somewhere within the final 24 hours of the victim's life. This true-crime documentary series follows investigators as they piece together events.

Killers torture and beat millionaire Ben Novak in a New York hotel room