Hunter Ingram SPOILER ALERT: This story contains spoilers for the entire first season of “Based on a True Story,” now streaming on Peacock. Most true crime documentaries and podcasts reach the inevitable moment when the killer makes a mistake and the authorities come calling. The season finale of Peacock’s new comedy “Based on a True Story” may have just arrived at that moment. All season, Ava (Kaley Cuoco) and Nathan (Chris Messina) have been pulled into a comedy of complicity of their own making after they partner with part-time plumber, part-time serial killer Matt (Tom Bateman) to document his Westside Ripper crimes for a podcast called “Based on a True Story.” But in the finale, he indoctrinates them into his world by killing their friend Ruby (Priscilla Quintana), and dumping her body on the doorstep of their newly leased beachfront dreamhouse for them to clean up.