When Jen Ramsaran disappeared, police searched online for clues and wondered if she escaped the real world for a fantasy world; journalist Andrea Canning covered the case in one of her first assignments for "Dateline."

After a young Army veteran disappeared, detectives uncovered a cryptic 911 call placed 11 days before she went missing, which exposed a twisted story — and the truth; reporter Josh Mankiewicz recalls the case.

Andrea Canning recalls the twists and turns in the case of Beverly Carter, a top-selling realtor who went missing after showing a house -- when her friends received mysterious text messages, they knew something was wrong.

Eduardo Valseca is taken hostage in an orchestrated abduction; Keith Morrison reflects on the family he spent years following; what happened to them might have destroyed many, but not the Valsecas.

A double homicide in upstate New York leads detectives on a cross-country investigation; Dennis Murphy reflects on a story full of twists and turns, including the surprising suspect at the center.

It's a mystery that defies easy answers, and "Dateline" has been following it for more than a decade; Steven Avery and his teenage nephew were convicted of killing Teresa Halbach; now, Andrea Canning shares her insight into the controversial case.

The heir to a legendary hotel is brutally murdered, and detectives learn he had no shortage of enemies; Dennis Murphy takes a fresh look at this extraordinary investigation, a hunt for a killer he calls the most ruthless he's ever seen.

A couple takes a scuba-diving trip to the British Virgin Islands. On their last dive, one of them surfaces but the other does not. Police quickly suspect the drowning was no accident. Now Dennis Murphy gives this unforgettable story a second look.

When a woman is found dead in her SUV, the investigation into her murder reveals a tangled web of sex and lies. Dennis Murphy looks back on his unusual interview with the lead suspect.

After 24-year-old Lisa Zeigert is killed in Agawam, MA, in 1992, her family keeps the case in the public eye for decades and it was featured on the show Unsolved Mysteries; Andrea Canning reflects on the harrowing mystery and discusses the inspiration she's drawn from Lisa's loved ones.

In Los Angeles, newlywed Sherri Rasmussen is killed in an apparent botched burglary in February 1986; nearly 20 years later, a detective discovers a clue that turns the case on its head; Josh Mankiewicz revisits a story with a twist that surprised him.

To many, it seemed like a romance between a former football player and homecoming queen; but when it ends in death, the police investigate; Dennis Murphy reflects on a secret relationship that led a churchgoing couple down a dangerous path.

A bombshell more than a decade after the crime reignites the investigation into the death of Sarah Pagel's mother. Andrea Canning looks back at her emotional interview with Sarah, whose mom touched so many lives.

When Britney Ujlaky disappears, a small Nevada town bands together to track down an unknown cowboy.

An apparent home invasion in Minnesota leaves Heidi Firkus dead and her husband hospitalized. For Blayne Alexander, getting to know Heidi through loved ones was a privilege; for investigators, learning about Heidi helps solve the case.

After a mother is found murdered in her Virginia home, her son embarks on a 20-year quest for justice. For Josh Mankiewicz, this cold case was one of the strangest he's ever covered. He looks back at the reasons why.

After a woman is murdered, a secret is exposed but a mystery still looms. Andrea Canning re-examines the story she first covered years ago. New developments lead to an unexpected conclusion in an interview you have to see to believe.

A mother is found dead in a house fire, but an autopsy reveals a brutal murder. The case goes cold until an unexpected confession sheds new light. Blayne Alexander looks back at a family shattered by loss, but determined to uncover the truth.

Two murders in Toronto ignite an investigation that spans four decades, but breakthroughs in investigative genetic genealogy help crack the case. Josh Mankiewicz revisits the mystery that took him to the coldest and most remote place he's ever been.

When a pharmacist is found shot dead, investigators go on a 15-year hunt for his killer. For Andrea Canning, this story has unique locations, fascinating potential suspects and riveting plot twists, but says the victim makes this mystery special.

A pregnant woman vanishes before her own baby shower and her worried family raises the alarm as detectives unravel a chilling mystery. For Josh Mankiewicz, it was a heartbreaking case that stayed with him long after the cameras stopped rolling.

A former ballerina shoots her husband in what she alleges was an act of self-defense. The ensuing investigation and dramatic trial spark protests and receives national attention.

A young Tennessee woman vanishes and misses her family's Thanksgiving dinner. Determined to track her down, her family takes matters into their own hands.

After a nurse and mother-of-three is murdered inside her Illinois home, investigators uncover security camera footage that could be key to solving the case.

An aspiring Playboy model is murdered in Miami, FL. A seven second clip of her last moments alive are caught on security video and could hold key clues. The haunting images make this case one of Dennis Murphy's most memorable.