Is it normal that i think my best friend will become a serial killer?

So, first off my best friend and I are both 18 and we just graduated high school. He is a very cool guy. (I wouldn't hang out with him if he wasn't.) He's quite funny, he can make me laugh even at the most inappropriate times. Not just me either. He's kind of the class clown while also being an intellectual, always knowing about a wide range of topics. Almost a walking encyclopaedia. Above all else, he is a gentleman and generous to friends and family. But even if he despises you, he is not only civil but also kind(?). Some would even say two faced. He calls it feigned civility. I call it being emotionally detached.

Lately, I've found myself sort of analysing his mannerisms and way of being. He's no stranger to criminality, yet he is currently aspiring to be a forensic analyst or even an officer of the law. But what really sets off a silent alarm in my head is his eyes. His cold gaze as he observes people, including me. As mentioned before, he can keep his cool and smile in the face of someone he doesn't like, yet to me, his eyes can always tell a different story (a violent one). And of course his discrete Dexter Morgan and Hannibal Lecter fascination also got me asking myself about his future intentions. (But then again, even I was routing for Dexter Morgan throughout the TV series, even if he was a serial killer) Oh right, and he has a small collection of combat knives on display in his room....

Did I forget to mention he really likes classical music? <- Total cliche.

Then there is our drunken stupor conversations, which I may not even remember completely, but dark topics have been discussed. Or how he once joked "I'm the kind of friend who will help you dispose of a body, but don't forget, I know how to dispose of a body" which we laughed off as nothing. But the questions remain..

Is it possible to detect future killers even if they have done nothing wrong yet? Or is it simply my fears being reflected ? Or perhaps it's his natural curiosity combined with his intimidating gaze that make me think he'll go serial one day. Nonetheless, I still think I'll end up reading about him in the newspapers one day. Is it possible to see something dark inside someone simply by looking in their eyes? Do we all have potential for evil, even if we've been good most of our lives?