What does a serial killer look like?
In the above video the serial killers interviewed do not seem obvious. Were you to have met them before they were caught, you probably would not have discerned they were about to murder you.
Yet there has to be a way to discern it. Jesus tells us we will know them by their fruit. Their spiritual fruit. If they are talking in such a way as to reveal their depravity, that should be warning enough for you to move on while you can.
On one end of the spectrum there is holiness, righteousness, truth, love and patience. On
the other end is unholiness, unrighteousness, lies, hate, and impatience. When you meet
someone expressing bad fruit, move on while you can.
John Wayne Gacy dressed up as a clown. He said his encounters were always by happenchance. Imagine him driving home with his clown costume and painted face and you hitchhiking.
He lived in a Mortuary and denies any contact with dead bodies, but
most of these serial killers had wierd sexual appetites and if you
listen closely to Gacy's testimony, you'll find immoral sex was the
center of his existence.