An inside look at key police interrogations that helped crack major criminal cases

During police investigations, interrogations -- the formal questioning of a potential suspect -- are critical and can lead to a big break in the case. Historically, investigators have been taught aggressive, coercive strategies aimed at one primary goal: obtaining a confession, whether true or false.

These tactics, popularized in television and movies, are known officially as the “Reid Technique.”

“The Reid Technique is used because it is effective in getting confessions. The issue that you run into though is…that you have a high rate of not just true confessions, but false confessions,” says Sujeeta Bhatt, a research scientist at the Institue for Defense Analyses.

Recently, there has been a growing movement among experts who study the science of interrogations and members of law enforcement to develop more thoughtful approaches aimed not at a confession, but at gathering information in the search for the truth.

"A real interrogation in the real world should not be a confrontational event," said Mark Fallon, a former NCIS special agent. "You're trying to develop a relationship and you’re trying to listen for information."

Fallon called that rapport-building an essential tool aimed at improving the communication between a suspect and an investigator.

Experts like Fallon have been at the forefront of research and training to analyze and improve the techniques for investigators when they bring a suspect into “the box.”

"The Interrogation Tapes," a special "20/20" true-crime docuseries premiering April 1 at 10 p.m. on ABC, will take a look at six cases through the lens of their interrogations, revealing the strategies detectives used to coax confessions from suspects.

As the stories unfold, experts in the science and tactics of interrogations including Bhatt and Fallon, along with ABC News legal correspondents Ryan Smith, Brian Buckmire and Jami Floyd, go inside this supercharged space, unpacking dynamic, tense and vulnerable moments at the heart of each case.

Audiences will gain insights into the special techniques employed by different interrogators, how some use the physical space, methods employed when looking for clues, analysis of a suspect’s speech and body language, and how this all can culminate in the truth – and in one case, a false confession.

Beyond the interrogation themselves, the episodes will feature new never-before-seen footage, as well as interviews with key investigators and family and friends of the victims and suspects.

The first episode will explore the December 2016 disappearance of Sarah Stern, a 19-year-old from Neptune, New Jersey, who was reported missing after her car was found abandoned on a bridge.

Police interviewed several people -- including Stern's childhood friend Liam McAtasney, who was the last person she was seen with -- in an effort to get more clues about her whereabouts. McAtasney's roommate Preston Taylor was also interviewed.

McAtasney and Taylor initially told investigators that Stern was talking about running away, and that they were concerned that she was suicidal. Interviews with other friends of Stern's, however, painted a different picture -- refuting the idea that Stern would just leave or take her own life.

McAtasney seemed compliant as he walked investigators through his day with Sarah. He failed, however, to include a key event in which they went to a local bank where Stern kept over $25,000 in a safety deposit box. Although investigators key in on troubling statements and omissions made during his police interviews, McAtasney was not initially considered a suspect.

Police catch a break when Anthony Curry, an up-and-coming filmmaker and classmate of McAtasney and Stern, called investigators with shocking new information that Stern may have actually been murdered. As a result, Curry goes undercover to help solve the case.

Experts unpack the intricacies of preparing a civilian to conduct an alternative form of an interrogation.

"You don't want to over prepare him. You want him to act as natural as possible” according to Bhatt.

Curry’s risky hidden-camera conversation leads to the capturing of a chilling confession.

The following five episodes in the series feature cases spanning 30 years.

In 2003, the fatal shootings of four high school classmates in the Houston suburb of Clear Lake became known as the Clear Lake Massacre. After years of chasing dead ends, a tipster points law enforcement in a surprising direction — a young woman, Christine Paolilla, once bullied in school was befriended by two of the victims who helped her become a beauty queen.

Investigators begin to grapple with a crucial question: Is this former “Miss Irresistible” a mere pawn in a cold-blooded killing or a calculated mastermind?

Another episode will look at the 2018 investigation into the murders of Shanann Watts and her two young children. When Shanann and her daughters first go missing, Chris Watts, her husband, appears on local news, pleading for their return.

But his demeanor and responses to questions in the interview lead investigators to believe something is amiss. After they bring him in for questioning and he later fails a polygraph, detectives allow a surprising guest into the interrogation room -- leading Chris to reveal a dark secret.

The next episode discusses the case of Karl Karlsen, a man whose wife and son died decades apart in what first appeared to be horrible accidents. However, suspicious insurance payouts and a secret recording put Karlsen at the forefront of an investigation, and what follows is an hours-long interrogation revealing years of deadly family secrets.

The following episode reviews the investigation into the drowning death of Vincent Viafore. After first appearing to be a tragic accident, investigators grow suspicious once they begin speaking with his fiancée.

Now, talking to ABC News for the first time, the lead detective of this case, Donald DeQuarto, unpacks how the interrogation of Viafore’s fiancée led him down a path of trying to discover if something more sinister happened.

The final episode tells the story of a false confession and a determined quest for the truth. After Angie Dodge is murdered, police zero in on 20-year-old Chris Tapp as one of the suspects. Convinced he was part of the crime, authorities relentlessly interrogate Tapp before he finally confesses.

Dodge’s own mother becomes certain of Tapp’s innocence after watching recordings of his interrogation, sparking a yearslong search for the truth before police can question the real killer.

ABC News Studios’ “The Interrogation Tapes: A Special Edition of 20/20” premieres Monday, April 1, at 10:00 p.m. EDT on ABC and next day on Hulu. Additional episodes air on Mondays through May 6.