1.8M views · 24K reactions | Every chilling retelling was another way to control, to shock, to relive the violence he believed he was entitled to. Watch #SignsOfAPsychopath Sunday on ID. | Investigation Discovery | Facebook

A knock at the door. A basket of flowers. A balloon that said “You’re the Greatest.” And a clown with a revolver. What seemed like a cheerful delivery turned into one of the most shocking crimes in Florida history. Now, People Magazine Investigates revisits the case that stunned the nation. Stream "People Magazine Investigates" on @HBOMax. And watch an all-new season premiere January 12 on ID. #PeopleMagazineInvestigates | Investigation Discovery

Bank Robber Wears Life-Like Mask

On Friday the 13th, Christine Markle and her daughters are found murdered. A signed confession points to John Markle, but the blood-stained Halloween mask left at the scene raises haunting questions. Watch “The Friday the 13th Murders” Wednesday on ID. | Investigation Discovery

33K views · 99 reactions | Watch “The Idaho College Murders” — Sunday, March 12 at 10/9c on ID or stream @discoveryplus | Investigation Discovery | Facebook

57K views · 276 reactions | Strange coincidences. Unbelievable twists. And mysteries that will make you question everything. The all-new season of The Curious Case of… unpacks the wildest true stories you’ve never heard. Watch the season premiere of "The Curious Case of…" tonight on ID and stream on @HBOMax #TheCuriousCaseOf | Investigation Discovery | Facebook

108K views · 423 reactions | Idyllic getaways unravel into haunting mysteries exposing the sinister secrets lurking beneath sunlit shores. Narrated and executive produced by Jessica Biel, FATAL DESTINATION premieres on Tuesday, June 3 at 10/9c on ID and Max | Investigation Discovery | Facebook

341K views · 4.4K reactions | One of the most sinister places in...