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.

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.

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.

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.

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.

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.

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.