When young mother and paramedic Annamarie Cochrane Rintala is found dead at the bottom of her basement stairs, it takes four trials and 13 years before justice is served. In Friday's Dateline, insiders close to the investigation speak out in new interviews about the final verdict.

INTERVIEWS WITH: Prosecutor Steve Gagne, defense attorneys Rosemary Scapicchio and Chauncey Wood, and others. 

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.

When 16-year-old Britney Ujlaky disappears, a small town in Nevada bands together to track down a potential suspect - an unknown cowboy; Soon, their focus turns to someone much closer to Britney.

When 17-year-old Alissa Turney is reported missing in Phoenix, it takes years before detectives treat her case as a homicide. A new investigation unearths dark family secrets, leading to a dramatic courtroom drama and an outcome no one saw coming.

INTERVIEWS WITH: Detective William Andersen, Alissa's brother James Turney, Deputy County Attorney Vince Imbordino, and others.

After Tahereh Ghassemi disappears from the Louisiana home she shares with her adult son, detectives discover that she'd recently come into a great deal of money. The investigation reveals an astonishing plot with international implications.

INTERVIEWS WITH: Hamed Ghassemi, lead investigator Todd Morris, East Baton Rouge Assistant District Attorney Dana Cummings, and others.

In a Dateline NBC exclusive, lead detectives speak out about the investigation into once-prominent South Carolina attorney Alex Murdaugh, convicted last March of murdering his wife Maggie and son Paul.

For the first time, South Carolina Law Enforcement Division investigators Britt Dove and David Owen speak out about the moment they discovered video evidence proving Alex was at the scene of the murders when they occurred. Dove explained to NBC News' Craig Melvin that after listening to the video "three to four times," he was in "disbelief." Owen added he knew at that moment the case had been blown wide open, saying: "I can prove that Alex was lying to me."

The Murdaugh Murders: Inside the Investigation also features an interview with the former Murdaugh family housekeeper Blanca Turrubiate Simpson, who opens up about her unique history with the Murdaughs, as well as Judge Clifton Newman, who presided over the murder trial. 

When United States Air Force Airman Nathan Paet is shot multiple times inside his garage, a trail of clues leads Las Vegas detectives to a secret love affair and a murderous plan.  

INTERVIEWS WITH: Las Vegas Homicide Detectives Tod Williams and Laura Andersen, Nathan's family members, and others.

Dateline investigates the murders of several women found dead along Gilgo Beach in Long Island, New York.

During The Hunt for the Gilgo Beach Killer, Heuermann's former neighbor Jimmy Mack speaks out in his first TV interview, telling Dateline that he "immediately" had a bad feeling about Heuermann. Additionally, Mack revealed that they had a "confrontation" after Heuermann allegedly threatened to cut the tires of a car in Mack's driveway that partially blocked the sidewalk.

The special also examines the death of Shannan Gilbert, whose remains were found on Gilgo Beach in December 2011. Speaking out for the first time since Heuermann's arrest, Shannan's sister calls for Suffolk County Police Department to reopen her sister's case.

After police discover the burned body of missing Miami man Camilo Salazar at the edge of the Florida Everglades, the wife of a local supermarket mogul comes forward to reveal a shocking secret and possible lead.

INTERVIEWS WITH: Family members, Detectives Chris Villano and Doug McCoy, Miami-Dade State Attorney Katherine Fernandez Rundle, prosecutors Gail Levine and Justin Funck, former Miami Herald reporter David Ovalle, reporter Christian Colon, and others.

The investigation into the mysterious disappearance of Canadian limo driver Dwayne Demkiw sparks an international manhunt for an elusive killer with multiple false identities.

INTERVIEWS WITH: Edmonton Homicide Detectives Brian Robertson and Rob Bilawey, Dwayne Demkiw's friends Kayla Polihronopoulus and Darren Boisvert, and others.

After nurse and mother-of-three Becky Bliefnick is found fatally shot inside her Illinois home, investigators uncover security camera footage that could be key to solving the case. 

INTERVIEWS WITH: Quincy Police Chief Adam Yates, Assistant States Attorneys Josh Jones and Laura Keck, Becky's sister Sarah Reilly, and others.

The murders of two young women near a Phoenix canal in the early 1990s remain unsolved for over 20 years until a team of cold case detectives take on the case. Friday's all-new Dateline examines how investigators used inventive techniques and groundbreaking advancements in forensic genealogy to unmask the killer.

INTERVIEWS WITH: Former Phoenix Police Department Sergeant Troy Hillman, Defense attorney RJ Parker, forensic genealogist Dr. Colleen Fitzpatrick, co-workers of the victims, and others.

A small town in the Ohio River Valley is left in shock after beloved local coal miner Brad McGarry is found fatally shot in the basement of his home. As investigators dig into his personal life, a secret affair reveals a surprising suspect.

INTERVIEWS WITH: Belmont County Chief Detective Ryan Allar, Bellaire Police Officer Hank Martin, former mine foreman Franco Pinacchio, Brad's friends, and others.

After an apparent home invasion in Minnesota leaves 25-year-old Heidi Firkus dead and her husband Nick hospitalized, detectives learn the young couple was facing financial troubles. In Friday's all-new Dateline, insiders connected to the case speak out about the decade-long search for justice. 

INTERVIEWS WITH: Heidi's brother Pete Erickson and sister-in-law Jolene Erickson, Nick's second wife Rachel, Nick's close friends, and others.

When young pregnant mother Bethany Decker goes missing in Virginia, her family embarks on a frantic search, but the case eventually goes cold. Years later, investigators speak with a woman who tells a harrowing story and may hold the key to solving the case.

INTERVIEWS WITH: Investigator Mark Bush and Steve Schochet, Bethany's family members, and others. 

A small Texas town is shattered when beloved teacher Manuela Allen vanishes from her home in the middle of the night. When a gruesome discovery is made a short time later at a local lake, investigators are left with more questions than.

INTERVIEWS WITH: Julius Mullins, Texas Ranger Michael Schraub, family members, and others.

The investigation into the poisoning death of Wisconsin mother-of-two Julie Jensen takes a surprising turn when detectives learn that Julie wrote a letter just days before her death pointing to a possible suspect. 

INTERVIEWS WITH: Pleasant Prairie Police Department Captain Barry Ollila, former Kenosha County District Attorney Bob Jambois, Private Investigator Dave Ellis, coworkers of Julie's husband Mark Jensen, and others.

When three women discover the body of Emily Noble in a wooded area near her home nearly four months after she went missing, investigators must determine if her death was a suicide or homicide. In Friday's new Dateline, Emily's husband, Matt Moore, speaks out in an exclusive interview about the case that rocked a small Ohio town.

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.

In the exclusive interview, Darrin speaks out about his relationship with Jamie's wife, Jennifer Faith, which began when they dated in high school. When the pair reconnected decades later, Darrin says he was manipulated by her false allegations of Jamie's abuse. Darrin tells Dateline that when he committed the fatal shooting, it felt like he was on a "mission in the military," adding, "I was doing what I had to do to protect Jennifer."

Losing Faith also features interviews with homicide detective Chris Walton, detective Eric Barnes, federal prosecutor Rick Calvert, reporter Cyrus Cezar AKA ‘Smash Da Topic,' Darrin's attorney Juan Sanchez, friends and family members, and others.

Following her husband's sudden death, a Utah mother-of-three writes a book to help her children through their grief; But when investigators learn the cause of death and dig deeper into their lives, she is charged with murder.

Law enforcement officers investigate a string of deadly shootings targeting women in the border city of Laredo, Texas.

After a mother is found murdered in her Virginia home, her son embarks on a 20-year quest for justice that leads him down a dark and twisted path.

After a district attorney and his wife are murdered in the same Texas town where a prosecutor was gunned down two months earlier, local law enforcement fears they may be in the sights of a serial killer.

The murder of a local 22-year-old sends shockwaves through the Arkansas Ozarks.

Exclusive new details on the investigation into the murders of four University of Idaho students.

New details come to light on the investigation into a notorious Idaho case.

A man convicted of the 1997 murder of Ricky Cowles Jr. in Lancaster, California, reveals new details on the case in an exclusive interview.

When a woman's fifth husband dies in a hospital under suspicious circumstances, an investigation reveals her to be a charismatic charmer with a mysterious past.

The man at the center of the international manhunt for an American fugitive accused of faking his own death to evade law enforcement agencies speaks out for the first time on network television.

The discovery of a young woman's body in an abandoned building in rural Texas sparks a multi-state investigation lasting nearly two decades.

The latest in the murder of Laci Peterson, including new details on the appeals of convicted killer Scott Peterson. Keith Morrison reports.

After 27-year-old Jonathan Crews dies mysteriously in his Texas apartment, his family takes matters into their own hands in an effort to find answers.

The parents of Kristin Smart speak out in their first network exclusive interview since the recent sentencing of their daughter's killer.

The lead investigator speaks out about the murder of world-renowned snake breeder Ben Renick, found shot to death in a facility crawling with thousands of snakes.

The murder of former NBA star and hometown hero Lorenzen Wright sends shockwaves through the city of Memphis; insiders speak out about new developments in the lengthy search for justice.

When a Colorado mother vanishes without a trace, the detective investigating her disappearance discovers a connection to a previous assault; for the first time on television, the survivor of that attack recounts her terrifying ordeal.

The latest in the trial of once prominent South Carolina lawyer Alex Murdaugh, including exclusive interviews with insiders close to the family.

A Florida father is determined to find out what happened to his daughter after her fatal fall from a penthouse apartment in Belgium. Dennis Murphy reports

The missing-persons case of 12-year-old Jonelle Matthews in Colorado remains a mystery for more than three decades until detectives narrow in on a suspect whose bizarre behavior after her disappearance hints at something much more sinister.

A quiet North Dakota college town is left in fear after student Mindy Morgenstern is found murdered in her off-campus apartment.

A deadly high-speed chase in Montana leads "Dateline" on a search through 50 years of history to unravel the mystery of how one man turned into a monster and committed one of the state's most notorious crimes.

Nearly 40 years after young wife and mother Cathy Krauseneck is found murdered with an axe in her upstate New York home, a new team of investigators joins the cold case to uncover the killer.

Latest in the investigation into the murder of four University of Idaho students.

After an apparent brazen home invasion during the holiday season in a quiet Connecticut community leaves Connie Dabate dead, investigators discover a silent witness that cracks the case wide open.