Netflix is all about true-crime documentaries these days, and they are always on the lookout for inspiration for their next hit series. Cold cases are of particular interest at the moment, especially after the recent success of Who Killed JonBenet on the platform. Netflix's next big documentary series could focus on an amateur true crime sleuth who has been busy solving multiple cold cases that have baffled law enforcement for decades, and he's done it using a homemade device.