From the 60s-90s, there were many serial killers who were caught and put into custody. But then, it just kinda... stopped? I'm aware that the amount of serial killers is unknowable, but surely, with increases in forensic technology and surveillance, there would be even more caught. But there aren't. What happened?
Bear in mind a lot of serial killers lore is "after returning the victim, Officer Thumb told Jeffrey Dahmer to have a nice day"