Who would want to kill Kristil Krug, a mom of three kids? Follow the clues in a race against time to catch a deadly stalker.

In 2010, Joseph and Summer McStay and their two young sons vanished from their Fallbrook, California, home. For nearly four years, the family’s fate remained unknown—until a grim discovery in the Mojave Desert turned the missing persons case into a homicide investigation.

21-year-old mother Denise Amber Lee disappears from her North Port, Florida, home. Follow the real 911 calls as they unravel in this life-and-death case.

In Horry County, South Carolina, Gregory Rice's disappearance in early October 2020 sparked a search that eventually uncovered a secret affair.

In Mayfield, Kentucky, 18-year-old single mother Jessica Currin was brutally murdered in 2000. The case haunted the town for years until a jury convicted Quincy Omar Cross in 2008. What began as a local tragedy has become a national conversation about truth, power, and accountability as Cross's claim of a wrong conviction gains momentum.

The Murdaugh family once held deep roots in South Carolina’s Lowcountry, where generations served as top prosecutors and wielded influence across legal and political circles. But behind the prestige was a web of corruption, financial crimes, and ultimately, murder.

At Fort Bragg, North Carolina, 24-year-old mother and Army maternity ward nurse Holly Wimunc suddenly vanished in July 2008. At her apartment, coworkers reportedly found smoke damage and signs of an intentionally set fire. While detectives scrambled to find her, her father, halfway across the country, was just learning his girl was gone.

A college student is murdered in her home, and while investigators work the case, evidence from a string of sexual assaults leads to a break; a survivor who helped authorities catch the killer speaks out for the first time;

A beloved hairstylist vanishes without a trace, launching a multistate investigation that ultimately uncovers a chilling trail of deception.

After 24-year-old mother Alyssa Burkett is brutally shot and killed outside her workplace, real-time surveillance video helps detectives uncover clues that lead to a suspect whose own confession suggests a possible mastermind still at large.

A wealthy grandmother goes on trial accused in the murder-for-hire of a family member.

A dogged detective will stop at nothing -- donning disguises, going under cover, and employing cutting edge forensics -- all to solve the murders of two young women

From Mr. Right to most wanted: Investigators uncover the double life of an international fugitive.

When Jessie Blodgett, a talented teen musician, is murdered in her home, another young woman is brutally attacked nearby, and one link that helps police catch the killer.

A mother's unwavering crusade for justice after her daughter's murder and the hidden clue that helped catch a killer living in plain sight.

In Blue Mountains, Ontario, first responders find a burned-out car with one victim inside, and the married couple who own the car are both missing. Police are left to untangle what happened as they search for answers and a possible killer.

After a young mother is found murdered, seemingly at the hands of a home intruder, investigators uncover a far more intricate plot than the initial evidence suggests.

Four teen girls are found murdered in a Texas yogurt shop. Decades later, DNA evidence and advanced forensics reveal a suspected serial killer.

When Bryan Pata, a college football player destined for the NFL, is murdered, his mother questions whether police have done enough to solve the case. 20/20 and ESPN investigate.

A wedding weekend turns into a real-life whodunit when the vacation rental's host vanishes overnight.

The shocking story of Utah mom Kouri Richins, accused of poisoning her husband and then writing a children's book about grief. The verdict is in. Her closest friend and a jury foreperson speak out

A disgruntled neighbor, Susan Lorincz, shoots and kills Ajike Owens, sparking national outrage. Exclusive "20/20" interviews and body camera video document the bitter feud and its aftermath.

A family drama unravels during a twisted murder plot involving veteran firefighter Robert Doerr. Police uncover a shocking clue from the funeral that leads to an unlikely killer.

Debbie Flores Narvaez, a beautiful Las Vegas showgirl, disappears without a trace. Who knew the dark secrets of what happened?

A mysterious house fire caught on camera leads investigators to the unsolved murder of 25-year-old mother Regina Rowe Hicks, found in her car submerged in a pond.

On a hot summer night in 2022 in Gwinnett County, Georgia, 16-year-old Susana Morales was visiting her friend's house when she seemingly disappeared. A tracking app on Susana's phone gave intriguing clues, but the search went on for months. Her family wouldn't stop until they found answers.

Kay Parsons, 41, was a Georgia mother who was found severely beaten in her Grovetown home on March 25, 2009, and died the following day. Initially, investigators considered it a tragic home invasion, but soon uncovered a tale of betrayal and planned violence.

When 19-year-old Kenia Monge goes missing and 30-year-old Lydia Tillman is found beaten in a nearby town, detectives learn that one of the victims holds the answers to both crimes in her hand.

A Michigan woman's survival story after being kidnapped by a man who stalked her for years and built a secret bunker to hold her captive.

After a young mom is abducted from her home, it will take a series of chilling 911 calls, including one from the victim herself, to solve the case. Her family speaks out in a new "20/20" interview.

An 11-year-old is kidnapped while biking home, leaving his parents searching for answers. Now, another previously abducted victim speaks out after helping solve the mysterious case.

The latest details and analysis in the case of the Massachusetts mom and the killing of her three young children.