After New York City fashion photographer Joel Schoenfeld is shot dead in his Greenwich Village studio, detectives uncover a dark secret and a twisted tale of revenge.

When a woman finds her daughter strangled to death in their Staten Island, N.Y., home, computer technicians uncover a dangerous online dating habit, but the real killer lies much closer to home.

When a woman is murdered in Milwaukee, her sons describe a masked man with a ponytail fleeing from the home, and police investigate the victim's rancorous ex-husband and a neighbor who claims his gun was stolen.

In Bronx, N.Y., police investigate the murder of 20-year-old Kimberly Antonakos who was set ablaze while still alive.

An intruder shoots Daniel Ott dead with a shotgun in a stunning case of mistaken identity that leads investigators into the heart of one of the most dangerous criminal rings in the country.

Pro football player Sean Taylor is shot dead by an intruder in his Miami home.

A car races up to the emergency room doors at a Mount Kisco, N.Y., hospital; driver Carlos Perez-Olivo has been shot in his side, while wife Peggy has been shot in the head; investigators must determine what horror has befallen this couple.

After 39-year-old Dawn Viens goes missing, her chef husband, David, reports she ran away to escape her problems; the investigation leads detectives to an unexpected killer who disposed of Viens' body in an unimaginable way.

Hollywood golden boy Gavin Smith, a 20th Century Fox executive and former star UCLA basketball player, goes missing; for years, his family and detectives search tirelessly for answers, but a group of heartless characters hold fast to their secrets.

Diane Girts is found dead in the bathtub of her home adjoining her husband's funeral home, and investigators cannot determine exactly how she died; as the case unfolds, detectives uncover troubling clues pointing to a cunning and dangerous killer.

Ann Anastasi returns home from shopping to find her husband, Anthony, lifeless in bed, a gun beside him; police soon find a second victim, Jacqueline Riggs, in the basement; later, they discover a dark tale of love, lust and violence.

Forty-two-year-old Miami mother Raquel Calderin vanishes without a trace on her way home from work in 2012; the investigation into disappearance leads detectives deep into a disturbing family picture, and the truth will haunt them for years to come.

When Robert Schwartz, a father of three, dies in a brutal murder in his own home made to look like a ritualistic killing, the investigation uncovers a killer much closer to home.

California real estate developer Jana Koklich vanishes in the summer of 2000, causing police to suspect her job led her into danger, until a local pastor comes forward with a shocking confession.

Miami businessman Henry Diaz goes missing the night before a family vacation.

On Long Island, a man pulls into a gas station claiming his wife has been shot dead by a motorist on the highway, but he's foggy on the details.

A mother is killed in her bedroom, and her teenage daughter confesses to the crime.

The body of 20-year-old student Sandra Bonaventure is discovered in a garbage bag on a sidewalk in New York City; the trail of clues lead to a cold-hearted killer who possesses an astonishing talent for deception.

Forty-seven-year-old mother Joyce Aparo is found strangled to death near a road 70 miles from her home in Glastonbury, Conn.; the investigation leads detectives into a dark world of abuse, sexual obsession and lies.

Film director Adrienne Shelly is discovered hanging by a bed sheet from the shower rod in her bathroom; while Shelly's death looks like a suicide, her husband insists it was murder, and detectives start to believe him.

Wisconsin police are shocked to find an elderly couple brutally murdered in their home, then their family members and neighbors start receiving death threats as well.

From the moment a homicide is reported, a file is assembled to document every facet of the investigation -- crime scene photos, notes and observations, forensic reports, witness interviews, suspect profiles -- and continues to grow with new information until an arrest is made and conviction attained. Investigation Discovery opens these "murder books" to tell haunting tales buried within the pages. Hourlong episodes take viewers back in time with details of decades-old cold cases using actual archival footage, crime-scene evidence and first-person interviews with lead investigators, unraveling the mystery and uncovering what broke the cases open.

Maybe it's the jealous ex, the co-worker seeking revenge, or perhaps a predator with an appetite for blood? Whatever the motives, crimes are most often solved by relentless investigators searching for the truth and following clues wherever they may lead. This series explores the emotional stories of those attempting to find closure in homicide investigations, from the victims' families to the dedicated police officers. Hourlong episodes present compelling versions of what may have happened and stylized re-enactments of events from different perspectives as new evidence emerges.

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.

"Who Killed Jane Doe?" presents a unique journey of discovery, loss, mystery and resolution. Featuring Investigation Discovery's distinctive stylized re-enactments, each hourlong episode weaves together two parallel stories: that of detectives who gather clues to identify a victim and the manner of death, and that of a family who knows very well who the victim is and is struggling to find her. The emotional tales honor the nameless and offer a final resting place to a missing loved one.

"Beyond the boundaries of ordinary life, there is another world that lies just outside of town, where places have no names." That's Investigation Discovery's introduction to "Murder Comes to Town," a true-crime series that reveals what can happen in solitary and desolate places. Hourlong episodes feature gripping tales of betrayal and murder buttressed by re-enactments and interviews with friends, family, and neighbors of the deceased, plus law enforcement personnel.

"Murder by Numbers" begins in a similar fashion to many true-crime series. After a body is found, an intense investigation commences, quickly turning the focus to a very likely subject. But just as the viewer eases into the case via cinematic re-enactments and through the eyes of detectives, a shocking discovery of a second body not only eliminates the original suspect, it redirects the investigation on a harrowing journey of pure criminal evil.

While most killers act alone, there's another type of murder that happens less frequently yet still produces horrific consequences. That's when people decide to kill as a group. This Investigation Discovery series details true-crime cases that involve victims who have been savagely murdered by their own friends. Stylized re-enactments featuring first-person accounts from law enforcement personnel and friends and family of the victims accompany each story.

Not every murder scene leaves behind clues in the form of bloody footprints, clothing fibers or fingerprint stains. Investigators earn their reputations by discovering evidence other than what is easy to see. This series spotlights devoted investigators who "go beyond the headlines," incorporating cutting-edge science to find the tiniest trace evidence and understand its relevance. The forensics-driven stories are told via stylized re-enactments, showing how the best investigators work to decipher which clues mean nothing and which ones will put a killer behind bars, all to bring justice to victims' loved ones.