Luis Frias makes John Walsh's most-wanted list after allegedly stabbing his common-law wife to death in front of their children; Callahan Walsh explores the case of Harold Butch Knight, who left a trail of clues after confessing to killing his wife.

John Walsh profiles triple homicide suspect Mike Bullinger who led a double life; Callahan Walsh looks at the case of Tomas Magallon Gonzalez, who allegedly sexually abused his stepdaughter for years before taking her life.

John Walsh investigates Alicia Osibin who is wanted in connection with the shooting death of her elderly mother; Callahan Walsh speaks to Andrea, an alleged victim of Frederick McLean's abuse, who is still desperate for McLean's capture.

The case of youthful con man Edgardo Perez, who allegedly preyed on older men until it turned deadly; Callahan Walsh travels to Boulder where teenage babysitter Chris Deininger confessed to abusing 29 kids in his care before fleeing.

John Walsh profiles Juan Lazaro Abrego who is believed to have murdered his ex-girlfriend, a beloved schoolteacher; Callahan Walsh investigates Derek Dean, a St. Louis man accused of shooting identical twins, killing one and wounding the other.

Salvador Vaca Garcia makes a tearful appearance on local news after his girlfriend disappears; Callahan Walsh looks at Brian Keith Freeman who allegedly slit his fiancé's throat when their engagement fell apart.

John Walsh tracks the story of convicted killer Glen Stark Chambers, who beat his young girlfriend to death and then escaped prison twice; Callahan Walsh investigates a murder suspect who eludes capture for 20 years.

John Walsh investigates how Eric Jones, the son of a preacher, allegedly turned to murder; Callahan Walsh tries to make sense of how a dispute over a dog could provoke Ricardo Villanueva Cordova to reportedly commit murder in broad daylight.

John Walsh spotlights Jihad Ramadan who allegedly stabbed a fellow university student to death; Callahan Walsh looks for Thayne Smika who reportedly shot his roommate in cold blood over back rent.

John Walsh investigates the accusation that Lamont Stephenson strangled his fiancé and her dog; Callahan Walsh explores police claims that Gloria Schulze is a drunk driver who repeatedly cheats the legal system.

John Walsh profiles John Blauvelt, a troubled U.S. Army veteran who is accused of waging war against his young wife; Callahan Walsh looks at Rudy Fernandez, whose romance with his high school sweetheart is believed to have turned deadly.

John Walsh reveals that a single mother is far from safe with ex-Marine Raymond R.J. McLeod who initially seemed like a knight in shining armor; Callahan Walsh discovers how rapper Maurice Nesbitt's constant abuse of his girlfriend turns deadly.

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.

Here today, gone tomorrow. Thousands of people go missing in the United States each year, leaving behind only a mystery without any clues. Their stories are told in "Disappeared" through the voices of family, friends and investigators trying to solve the case, with each hourlong episode recounting the final stages that led to a person's disappearance. Interviews with experts including psychologists and forensic specialists provide new insights into what may have happened -- whether foul play was involved or the subject simply ran away.

"Accident, Murder, or Suicide" investigates the deaths that are just a little bit too mysterious. It explores the unbelievable true stories in this hourlong program. Each episode retraces the investigation from the start to the end. Investigators take viewers through the twists, turns, and unexpected surprises as they dissect the red flags, show evidence, and point out the strange behavior that puts everything into question.

What lurks in the shadows during graveyard shifts comes to light in this series, a quintessential Investigation Discovery offering that features nail-biting re-enactments of actual crimes in which darkness hides predators hungry for a midnight snack. Told through interviews with victims' family members and law enforcement, each story begins after a brutal crime is committed in the quiet of the night, and community members are left wondering who might be next. Investigators get to work, knowing that each time the sun sets, the body count might rise.

Never forgetting what happened to loved ones who have been murdered is a way of paying respect, however horrifying and raw those memories may be. The recollections can come in handy too, like when they contain critical clues that help detectives piece together the final hours of the victim's life. This series examines that aspect of homicide cases, with each hourlong story told through the memories of family members, friends, and investigators, plus images from the time of the crime that still haunt and are unforgettable.