Dateline: Secrets Uncovered

A mom suddenly vanishes and a dad is under suspicion, but there was no body, weapon or eyewitness, and surprises cropped up along the way.

Investigating whether a toddler left in the car for seven hours while his dad was at work was a heartbreaking accident or murder.

Melissa Lewis disappears, leaving signs of a struggle and a strange orange mist behind her; her boss goes missing and leaves behind an even bigger mess, and a missing fortune.

After a young Army veteran disappears, detectives uncover a cryptic 911 call placed 11 days before she went missing, which exposes a twisted story -- and the truth.

A foreign exchange student and soccer player's participation in a dangerous game leads to deadly consequences.

When detectives track down the killer of a Las Vegas cocktail waitress and mother, it becomes clear that the investigation has just begun.

What happened that September night when romance turned to danger? Something went terribly wrong and a woman slipped over the edge of a cliff. Did she fall by accident or was she pushed? It would take almost 20 years to find answers.

It was a plot straight out of an Alfred Hitchcock film. A woman peers into a neighbor's yard and catches a glimpse of something unsettling. What she saw and what she did set a chain of events in motion that would divide a family and a jury.

It began with a young mom abducted at gunpoint. Her family and veteran investigators spent desperate days trying to find out where she was but they never could have guessed WHO had her and WHY.

Michelle Young was married to her college sweetheart and pregnant with their second child when she was murdered. In the search for her killer, detectives uncovered a marriage riddled with secrets but cracking this complicated case took years.

How well do you really know your neighbors? It's a question at the center of this mystery. The neighbors you're about to meet enjoyed mixing business with pleasure then a murder made them face the reality that a killer was in their midst.

Judy Carlson lived in a painful limbo. Her son disappeared without a trace. Years went by and she may never have known his fate if not for a rookie detective's dogged work but to solve this cold case, the investigator also need the help of a killer.

She was a beaming bride. It was a haunting death. Sarah and Ryan were newlyweds when she drowned in the bathtub. Did she die of natural causes or was it deliberate? It took three trials to find the truth.

It all began when a bestselling author found his wife at the base of the stairs. Was this a fall or was it a crime? The story made headlines and we've been covering it for more than a decade. Here, Michael Peterson answers our questions.

A woman is murdered in a home invasion. Then, her best friend and neighbor is shot the following night. Investigators unearth disturbing secrets that suggest the cases may be linked.

Newlywed Dalia Dippolito returned home from the gym to the awful news that her husband had been killed. In a case where almost nothing was as it seemed, investigators wanted to know: Was Dalia diabolical or an unwitting pawn in a hoax gone wrong?

Gavin Smith was dashing. When he vanished, LA detectives were unsure if they were investigating a crime or a suicide. His wife said he'd gotten lost in drugs and flings. Police wondered if the key to finding Gavin was hidden in one of those affairs.

Ashlea Harris had no shortage of admirers. So when she was found dead after a suspicious fire consumed her apartment, police were baffled. This was no accident but were the clues to who killed Ashlea now up in smoke?

Craig and Laura Rideout appeared happy but, after a contentious separation revealed an ugly secret, one of them would soon be dead. Clues pointed to four possible killers and left investigators wondering if this murder was all in the family.

It was an unthinkable crime. Brittany Eldridge was nearly nine months pregnant when she was found dead in her apartment. Investigators focused on two men with possible motives.

For many, the holiday season is filled with joy but, for the Jennings family, the night before Christmas became a waking nightmare. A gunshot rang out and investigators had to unravel whether a secret lead to a tragic suicide or if this was murder.

It started with a party, high school seniors celebrating graduation. Before the night was through, one man was dead and two teens were facing a long fight for justice.

The fire broke out before dawn. After the smoke cleared, a mother of two young children was found dead. It was the tragic end to a life that held so much promise, but for investigators, it was just the beginning. Was this an accident or murder?

Kevin and Morgan Mengel were happy at first, but when the marriage went bad, he went missing. Police wondered if he simply left, but a family’s relentless pursuit lead to a stunning confrontation and, eventually, the truth.

Sandi Johnson always put her kids first. When she vanished without a word, her loved ones were frantic. Police discovered dark secrets in Sandi’s marriage and several men in her life. Which one of them had something to hide?

Cousins Nick Brady and Haile Kifer were best friends. To their family, they seemed like typical teenagers. Turns out, the cousins had a secret that led to tragedy. The story divided a small town and sparked a national debate.

After college student Angie Samota was stabbed to death, police had no shortage of suspects. A crucial clue narrowed their list to one name, but it would be years before technology and a tenacious friend came together to help unravel this mystery.

Frank Rodriguez was a Navy vet who dedicated his life to helping needy children, not a guy with many enemies. Figuring out who would want him dead was a challenge. How he died was also a mystery investigators needed to solve to catch his killer.

When Eric Somuah was found shot in his bed, it was hard to imagine who would want the outgoing salesman dead. One dogged detective refused to give up. His investigation put him on a path filled with twists, turns and an ending few saw coming.

The life of a married father of two and successful real estate appraiser ends all too soon; investigators wonder if money is a motive, or if the murder is the result of a family rift.

Heidi Allen was working at a store to earn cash for college and was last seen there when she vanished. A man was convicted of murdering her, but years later someone else confessed to friends that he did it, blowing the old case wide open.

Corey Parker had plenty of admirers, but maybe one of them liked her too much. Her murder jolted a sleepy seaside community with the chilling realization that a killer was walking among them.

Fences make good neighbors, but this one triggered a deadly fight. Only two men were there and the man who shot first told investigators his story. However, the crime scene was telling another story.

A Philadelphia murder reveals decades of misconduct in the city's criminal justice system and raises questions about whether police caught the right person.

When Courtney Copeland is shot and killed, his mother investigates whether police detectives did enough to try to solve the case.

Keith Morrison reports on a dramatic undercover operation in Palm Beach, FL, to save a wife and mother who has no idea she is in danger.

When 18-year-old Anjelica 'AJ' Hadsell disappears, the investigation into her inner circle reveals a sinister betrayal.

When Nichole Payne and her son Taylor are found dead in their home, investigators wonder if this is a murder-suicide or if someone wants it to look that way. The mystery takes nearly a decade to unravel.

When 19-year-old Anton Black dies while being taken into police custody, the community seeks justice. A yearlong Dateline investigation looks at missed warning signs and the officer at the center of the case.

After trumpet player Scott Sessions fails to show up for a scheduled gig, his family learns his body was abandoned in the remote Colorado Rockies; as the investigation narrows in on two suspects, a second murder catches police by surprise.

Firefighters make a grisly discovery of the body of 39-year-old wife and mother Carmella Knight after responding to a house fire outside Toronto. An elaborate undercover sting reveals a devious murder-for-hire plot.

A woman is found executed on a rural road 25 miles from downtown Laredo.

A teenager's life is turned upside down by a shocking discovery is what seems like a fatal accident reveals itself to be something much more disturbing.

When high school student Megan Nichols vanishes from her Illinois home, her mother finds a note saying that she ran away. A grisly discovery made three years later changes the course of the investigation.

A small Ohio town is left in shock after a local coal miner is found fatally shot in his basement. As investigators dig into his personal life, a secret affair reveals a surprising suspect.

A beloved Staten Island teacher is found dead in the home she shared with her husband; an unknown number in her cell phone leads investigators to ultimately unearth her killer.

When a young pregnant mother goes missing in Virginia, her family embarks on a search, but the case goes cold. Years later, investigators find a woman who may hold the key to solving the case.

A young father's murder at work leads investigators to deep secrets about sex, friendship, religion and family.

After pro cyclist Moriah Wilson is murdered in Austin, investigators unravel a shocking case.

When deadly gunfire erupts in an Austin, Texas home in the middle of the night, detectives look at homeowners' jewelry business.

After a 25-year-old mother is gunned down in broad daylight by a murderer wearing a disguise, detectives confront a most unlikely suspect.

Stranger than fiction, a mom suddenly vanished. A dad under suspicion. There was no body, no weapon, no eyewitness and surprises along the way. Now, after all the twists and turns of four murder trials, the final verdict is in.

The case made national headlines: A toddler left in the car for seven hours while his dad was at work. Was this a heartbreaking accident? Police said it was murder. Could any parent ever do this on purpose?

Melissa Lewis disappeared leaving signs of a struggle and a strange orange mist behind her. Later, her boss went missing and left behind an even bigger mess, including a missing fortune. Two crimes leaving one lingering mystery.

An Army veteran vanishes before her college graduation. A massive search turns up nothing, but detectives do find a clue: a cryptic 911 call that helps uncover the truth and exposes a twisted story of unrequited love.

German foreign exchange student and soccer player, Diren Dede's dream of studying in America came true when he began his junior year at a Montana high school. When he decides to play a reckless teenage game, the consequences turn deadly.

When detectives track down the killer of a Las Vegas cocktail waitress and mother, it becomes clear that the investigation has just begun.

Newlywed Dalia Dippolito returns home from the gym to the awful news that her husband had been killed; in a case where almost nothing is as it seems, investigators want to know if Dalia is diabolical or an unwitting pawn in a hoax gone wrong.

When the dashing Gavin Smith vanishes, LA detectives are unsure if they are investigating a crime or a suicide; his wife claims he had gotten lost in drugs and flings; police wonder if the key to finding Gavin is hidden in one of those affairs.

Ashlea Harris has no shortage of admirers, so when she is found dead after a suspicious fire consumes her apartment, police are baffled; the fire is no accident but the clues to who killed Ashlea may be up in smoke.