When a correctional officer is murdered, it seems like an act of vengeance, but a love triangle is exposed; after learning his wife is having an affair, a husband plans to kill her lover and enlists the help of his brothers to carry out the task.

A pair of larger-than-life identical twins commit a series of brutal attacks in a small Tennessee town; with each crime, the brothers grow more emboldened; as time goes on and with little evidence against them, there's no telling how far they'll go.

Over a brutal 7-month stretch, a trio of brothers commit a series of increasingly violent crimes across the city of Richmond, leaving behind a growing body count; even after their apprehension, these brothers prove difficult to contain.

In the summer of 1991, a pair of half-siblings creates panic across southern California when they embark on a spree of random crimes of the worst kind, targeting people out doing everyday tasks.

After a man is found brutally murdered inside his own bar, a murder mystery unfolds over the span of years; detectives believe it's a business deal gone bad and must remain steadfastly dedicated to the case after hitting several dead ends.

The Carr brothers arrive in Wichita, Kan., intending to commit robberies, but their plans quickly escalate to a murderous spree the likes of which Kansas had never seen; their reign of terror becomes known as the "Wichita Massacre."

Raised in a strict home, Matthew and Tyler believe it's their duty to cleanse the world of those living in sin; when two men are found dead, the brother's connection to them points toward a hateful trail of crime.

Sheltered teenage brothers Robert and Michael Bever idolize serial killers and dream of being the most prolific murderers in history; with an arsenal of weapons, their quest for notoriety begins at home in their quiet Oklahoma suburb.

After their brother is convicted of murder, three siblings hatch a deadly plot to avenge him by targeting the star witness in his trial; the plan goes awry when the wrong person is on the receiving end of their vengeance.

Twin sisters, raised with a deep disdain for law enforcement, are arrested for shooting a neighbor's dog, then escape custody and go on the run, leading to one of the deadliest shootouts in Colorado history.

The holiday season between Thanksgiving and New Year's is often thought of as a celebratory period to spend time with friends and family. That is not always the case, though, as the period is not immune from experiencing the same types of violent crimes that occur throughout the year. This series documents stories of tragedy that struck during the holidays, with firsthand accounts from people who had friends or family members killed during the joyous time. Sometimes the victim is killed by someone close to them, such as a case of sibling rivalry turned deadly, but sometimes the killing is done by a stranger who interrupts a holiday gathering with gunfire.

Uncovering the dark and twisted motives that led to gruesome killings in the pursuit of a deeper understanding of the relationships behind the horrific killings and of the psychology of the people who committed them.

Each episode of this true-crime reality series examines a different felon, usually a female, who has committed murder or attempted murder. The victim is usually the perpetrator's partner. The documentary-style series features interviews with friends and family members of the accused and victims, law-enforcement officials, attorneys and other people with first-hand knowledge of the cases.

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.

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.

"Relentless With Kate Snow" takes viewers on an emotional journey with grieving families as they work tirelessly, often putting their own lives in danger, to find the culprits responsible for the deaths of those they loved most. Their relentless pursuit of justice paired with the opportunity to work alongside law enforcement creates a powerful and dynamic force that won't rest until due process is served. From a mother dedicated to putting her son's killer behind bars after he's gunned down at a recording studio to a 20-year search for a victim's killer that was so aggressive it transformed an unsolved, cold case into an active investigation, the series reveals gripping firsthand accounts from the families who will stop at nothing to get the justice the victims deserve.

Marriage is supposed to be a happy time in a couple's life. With engagements, weddings, and picturesque honeymoons -- hope and happiness were in abundance until a tragic and very mysterious death occurs to cut short these joyous celebrations. Viewers learn when the red flags first began -- was it because of depression or manipulation and did it overshadow a wonderful time? Is it because of prophetic dreams and the killer was fulfilling a divine mandate, or is there something lurking beneath the surface that no one knew about.

Retired NYPD Detective Kevin Gannon questions if the country's most notorious string of mysterious, accidental drownings are accidents or homicides and wonders if they could all be connected to The Smiley Face Killers.

Raw, unbridled and chilling depictions of human desires surface in "In Ice Cold Blood." True crime is depicted at another level as Ice-T takes viewers straight into the stories. Money, sex, lust, and greed run rampant with very real consequences. Family members, friends and detectives recount each case -- a missing military veteran, a student murdered in a crime of passion, and secret payouts are only some of the cases. These stories are told through re-enactments, in-depth interviews and archived footage.

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.