Seems a lot of these types or serial killers were in the 60's-90's. You don't hear much these days about it.
They're everywhere and as common (more so?) than ever. I know. I have dealt with many, face to face.
Citizens who do not work in law enforcement tend to think every case of excess violence and depravity is presented in the media. However, truth is, a majority of these cases remain on the "down low". Agencies would rather they stay out of the limelight, usually. So if the reporters don't catch wind, it's never showcased in newspapers, etc.
(Also, I believe society at large has become so desensitized to outlandish violence and sex that the media doesn't become as infatuated with tales of the macabre unless the story is especially grim and/or publicly relevant.)