Mark Twitchell was an aspiring filmmaker with a successful cult film, a wife and a young child. But he harbored a dark secret, the inexplicable desire to become a serial killer, partly inspired by the fictional character Dexter from the eponymous show. This week, Savannah explores how Mark was able to catfish two unsuspecting men from dating sites into his makeshift "kill room," which ultimately led to him murdering Johnny Altinger on October 10, 2008. Savannah also explores the many manifestos he wrote that make it clear that, had investigators not caught him, he would've certainly killed again. Love Killer Instincts but hate the ads? Subscribe to the ad-free version here!: https://killerinstinct.supercast.tech/ Get 10% Off by visiting BetterHelp.com/instinct! Download Best Fiends FREE today on the App Store or Google Play! Get 15% off their Raycon order at BUYRAYCON.com/killer SimpliSafe is offering 20% off your entire new system and your first month of monitoring service FREE, when you enroll in Interactive Monitoring. Visit SIMPLISAFE.com/killer for more info! If you have any thoughts on this case or any other case, or just want to get in touch with Savannah about the show, email her at killerinstinctpodcast@gmail.com.  Follow Savannah on IG: @savannahbrymer  Follow Savannah on Twitter: @savannahbrymer   Learn more about your ad choices. Visit podcastchoices.com/adchoices