“The number of documented serial murders has gone through the roof. I don’t think we have any real idea if the actual number is increasing or not.”
I’ve theorized that there’s probably at least one out there, who hasn’t even made his way onto the radar yet, who has so many kills that he makes all others seem small.
‘Mr. X’
So good that, not only is his identity not known, his existence isn’t even suspected because he’s so good that law enforcement hasn’t connected the dots between missing/dead people to realize that there even is a serial killer operating.