In 2016, in the shadow of Manhattan's skyline, a killer stalks women undetected. But a quick-thinking friend, a final phone call, and a social media chat log point to a serial killer who may never have been caught.

When police find Atlanta rapper Rahim Grant gunned down in his apartment along with the critically injured mother of his child, the only way to learn who pulled the trigger - and why - could be locked in a series of shocking videos on Rahim's phone.

In 2012, Brandy Rosine drives an hour into Pennsylvania from Youngstown, OH, but as night falls, the 20-year-old college student stops answering her family's calls. It's up to her mom to follow a trail of digital breadcrumbs Brandy left behind to find her daughter's killers.

In the winter of 2013, 14-year-old Shaniesha Forbes never made it home after school in Brooklyn, NY. Her charred remains turn up on a Brooklyn beach days later, but this teen leaves behind a mountain of digital evidence for the NYPD to sift through to find her murderer.

In rural Missouri, reptile breeder Ben Renick is found dead–surrounded by his collection of exotic snakes. Investigators have to wade through dozens of potential suspects before finding a text chain from Ben that leads to a true snake.

When 32-year-old John Ray is murdered in his Atlanta home, investigators are stumped. For seven years, his case goes unsolved until cold case detectives take another look at the evidence and find that John had identified his killer all along.

Sasha Krause, a devout Mennonite, disappears from her church's parking lot one night. Investigators pursue digital evidence across state lines, leading to a grisly find and a hate-filled killer.

Shockwaves rip through the college campus at the University of Missouri when 21-year-old Jesse Valencia is found, his throat slashed. With a litany of suspects – and a secret revealed by Jesse – investigators must untangle a web of lies to uncover an unlikely killer.

Armada, Michigan could be ripped from a Norman Rockwell painting, but the town changes forever when April Millsap's body is found. Police search for the teen's missing phone and discover a fitness app could hold the key to finding her killer.

Jodi Sanderholm is responsible and dependable, so when she disappears a few days before her first niece is to be born, detectives must follow a gruesome trail of Jodi's breadcrumbs they hope will uncover a secret monster among them

When 15-year-old Candice Parchment goes missing, the police write her off as a runaway. Months later, her body is found blocks from her home. Investigators are stumped until Candice's own writing helps uncover the horrifying truth behind her murder.

When beloved teacher and mother-to-be Laura Wallen disappears before the first day of school, a seemingly innocent photo could be the key to unravelling an intricate web of deception and secret lovers that shatters a tightknit Maryland community.

Mindy Morganstern refuses to let a devastating Muscular Sclerosis diagnosis defeat her; when she's brutally killed, it's her refusal to go down without a fight becomes the key to solving her murder and a series of horrific crimes.

Nikki Kuhnhausen lives loud and proud on social media. Born male, Nikki has openly identified as female since middle school. When the 17-year-old goes missing, her own social media helps police unravel the mystery of an unspeakable hate crime.

When Kevin Bacon never returns home from a Christmas Eve hookup, his friends fear the disappearance is related to recent terrifying abductions, while detectives decipher a series of screenshots they hope will reveal Kevin's fate.

Morgan Fox is a model employee with a bright future, but when she's found shot dead in a car just outside her own front door, investigators hope Morgan's own words can determine if she's the victim of a toxic coworker, or someone closer to home.

After the body of Brittany Clardy is discovered, frozen solid, in the backseat of her car, it's the discovery of a mysterious burner cell phone that reveals a secret life, and a list of suspects that may include a budding serial killer.

After a series of troubling posts appear on her social media, single-mother Julie Gonzalez vanishes. Desperate to learn the truth, her family works with the police and media, but it's Julie's own words that could reveal her fate and catch her killer.

Twin sisters Jholie and Zhane Moussa share everything with each other, including their darkest secrets. So, when Jholie vanishes after meeting a mysterious boy, Zhane might be the only one who can help detectives learn the truth.