Like trying to decipher the value of a book without ever opening it, judging a person by his or her outward appearance can be a mistake. Someone may look perfect on the outside, but even the most kind-hearted soul has a dark side looming. "Diabolical" is a docuseries that delves into the minds of murderers, asking a simple question: "Why did they do it?" The acts were committed with extreme premeditation -- many were months or even years in the making. Tension builds in each episode as law enforcement taps into the methods of devious masterminds, aided by insights from forensic psychologists and psychiatrists as well as criminal profilers.
Episodes Season Season 3 · 0/10 Season 2 · 0/10 Season 1 · 0/10 0/10 watched · 2020
S03E01 Daddy's Little Nightmare 2020-03-10 42m
In 2017, Federal Heights, CO, is filled with fear when 69-year-old veteran Bill Mussack is reported missing, gone without a trace; police act fast to uncover a diabolical killer with a heinous plot before the malicious murderer strikes again. more
S03E02 Hands That Rob the Cradle 2020-03-17 42m
In early 1980, two eerily similar crimes occur 400 miles apart; they both leave young mother dead and an infant child stolen; years later, police unravel a plot so cold-blooded, it leaves everyone even seasoned homicide detectives in utter shock. more
S03E03 Masking Evil 2020-03-24 42m
A burning car is found by the side of a highway on the same night a single mother of two is reported missing; the two events are related and connecting the dots leads investigators to a notorious criminal who has been hiding in plain sight. more
S03E04 Lie For Me 2020-03-31 42m
Air Force veteran Michael Giles disappears along with his savings of $206,000 and detectives find a that Kwaneta Harris has been draining his accounts. more
S03E05 Sins of a Mother 2020-04-07 42m
In 1994, Lake Orion, MI, is rocked by a murder; at first, the crime is a mystery -- but in a small town where everyone knows each other, rumors start flying. Police soon expose a strange and twisted plot that no one saw coming. more
S03E06 Teach Me To Kill 2020-04-14 42m
In Las Vegas, a beloved father of four is found dead in his car; he's been bound, gagged, and asphyxiated. Witnesses lead detectives to a local man named John Brian Ray, but this troubled man is just a pawn in the game of a criminal mastermind. more
S03E07 Devil Wears False Eyelashes 2020-04-21 42m
Three men die over a span of a dozen years, with no suspicion of wrongdoing and no files charged. But when a deadly car explosion rips through downtown Pensacola, FL, a new investigation begins; all suspicion points toward just one person. more
S03E08 Caught In the Cover-Up 2020-04-28 42m
In West Bloomfield, MI, a simple affair between two coworkers turns complex as the two lovers are willing to do anything, even commit murder, to protect their darkest secret. more
S03E09 Killer Track Record 2020-05-05 42m
Three women die of the same mysterious illness, and the hunt is on to prove their deaths were no accident; investigators don't realize they're being played for fools by a sinister killer lurking undetected. more
S03E10 Evil Sister Act 2020-05-12 42m
When Samuel Johnson Jr. suddenly vanishes, investigators find themselves face-to-face with two sisters who know something; through a series of interrogations, they reveal an elaborate murder plot meticulously engineered by a puppeteer. more 
