After two years following a lead, the investigators finally have evidence in hand that could answer the 12-year-old mystery of what happened to Natalee Holloway.

TJ races to the location where the co-conspirator claims he dug up Natalee's remains in 2010; working with the Aruban authorities, they search for DNA that could lead to convicting those involved in Natalee's disappearance.

TJ and his team head to Aruba to begin phase two of their investigation - attempting to obtain DNA evidence from Natalee's alleged burial site; Dave must convince his informant to go the extra mile.

The sting operation in New Orleans continues as the investigation team begins running out of time to obtain the necessary information from the co-conspirator.

Dave Holloway and a team of investigators pursue a lead that may shed light on his daughter's disappearance, with the goal of obtaining a taped confession and concrete evidence.

Natalee Holloway disappears from Aruba in May 2005, and her father Dave never stops looking for her; he receives a new lead that could be the key to solving the 12-year-old mystery, but he has suspicions about the source.

Social media was in its infancy in 2004, but the explosion in its popularity in the years since then has kept alive a missing-person case. Nursing student Maura Murray vanished in February 2004 after witnesses heard what sounded like a car crash. The case has led a legion of armchair detectives to come up with their own theories about the apparent crime on blogs, websites and podcasts. In this series, investigative journalist Maggie Freleng tries to unravel a slew of unexplored leads, eyewitness discrepancies and missing evidence that have cropped up online. She receives rare access to Maura's family and friends and talks with people who have dedicated countless hours to searching for the truth in the case. Freleng retraces Maura's last-known steps to try to find out what really happened and tackle the unanswered questions that remain -- perhaps most importantly, did Maura choose to disappear or was she a victim of foul play?

Some of the world's most notorious murders are the subject of "It Takes a Killer," which investigates the crimes from the perspective of the killers, trying to get inside their minds and determine their motives. Leading homicide investigators and experts from such agencies as the FBI and Scotland Yard take a look at the evidence pulled from crime scenes and profile the killer's behavior to try to piece together the details of each murder, explaining when, why and how each criminal committed the crime. For the wannabe detectives watching the show, the experts also reveal how the crime was solved -- which often requires authorities to think like a killer.

The first three days after somebody is abducted are extremely important. Statistically, the chances of finding the abductee alive diminish significantly after the first 72 hours. "Three Days to Live" chronicles kidnapping cases, using re-creations and first-hand testimony from authorities and loved ones to illustrate what went on -- from the crucial periods early on in the cases, which all feature females who were taken, through the twists and turns the kidnappings took before reaching their conclusions. Journalist SuChin Pak narrates the hourlong series.

Most true-crime shows let viewers know the identity of the victim right away, before working their way into revealing the identity of the perpetrator. That's not how things work on "Killision Course," which conceals all of the participants' roles until the episode's final act. While working toward the conclusion, each hourlong episode re-creates a murder case involving a victim, accomplice and killer. Stories often involve friends or lovers who commit crimes against people who once trusted them. It's all part of the road leading up to the big reveal, which is when viewers learn what role each party played in the fatal act.

Oxygen's long-running "Snapped" true-crime series takes a look at cases involving women who are accused of murder. In "Snapped: She Made Me Do It," women are the supposed masterminds behind deadly acts, but aren't necessarily the ones accused of the crimes. As is customary with these types of shows, witness testimony, interviews with experts and dramatic reenactments are used to tell the story of each case. Viewers get both sides of the story in each case before finding out the jury's verdict. Romance is often at the core of the attacks.

Social media can be a good thing when used properly, allowing people to catch up with friends and family who don't live nearby. Things can go wrong, though, when it's not used the right way. This series shows extreme examples of the negative outcomes that can result from social media usage. Episodes tell the stories of cases in which social media activity had dangerous -- sometimes deadly -- consequences. Cinematic re-enactments, witness testimony and expert interviews are used to present the tales that begin with something as simple as an online post or tweet and end with violence. Cases include an online feud between friends that results in a physical altercation and a seemingly innocent online connection to leads to a homicide.

In a project that hits close to home, National Geographic Channel forays into the true-crime genre by documenting biologist and National Geographic explorer Roman Dial's investigation into the 2014 disappearance of his son. An experienced outdoorsman, Cody Roman Dial vanished while trying to complete a solo expedition through the Corcovado National Park in Costa Rica, one of Central America's most dangerous jungles. "Missing Dial" chronicles how Roman, along with a former DEA special agent and a retired United States Air Force pararescue jumper/wilderness expert, spent nearly eight months in Costa Rica interviewing witnesses, interrogating suspects and trekking deep into the jungle in pursuit of new leads. They retrace Cody's last-known whereabouts and use hidden cameras and fake identities to uncover a web of lies, surprising clues and a shocking twist.

Think "Cold Case" meets "CSI" with a bit of "Rizzoli & Isles" mixed in, then make it real. That's the formula for this unscripted procedural drama that follows two veteran female investigators as they attempt to crack murder cases that have lingered for years without answers and closure. Kelly Siegler is an attorney and former Texas prosecutor who successfully tried 68 murder cases in her 21 years on the job, including 20 capital murder death penalty cases in which she secured the death penalty in 19 of those trials. She gets help from veteran detectives, who dig into small-town murder cases that have gone unsolved for years in the hope of getting justice for the victims and their loved ones.

Oxygen's long-running true-crime series "Snapped" tells stories of people who commit murder or attempt murder, with the cases usually involving a woman trying to kill her partner. This extension of the franchise shifts the focus to couples who commit crimes. Using re-creations and firsthand accounts, each episode digs into a case, telling the story of the couple's romance, how the relationship evolved from love to manipulation, and what ultimately led the couple to commit the crime. The stories range from teenage lovers who go on a multistate crime spree to lesbian lovers who want to eliminate one of their husbands.