Kev - serial killer?

Did anyone else get kind of weird vibes from Kev like something was really off with the guy? Had this not been a lighthearted film about immaturity and outgrowing one's superficiality, the final scene would have been extended by like a minute or two. Kev drives home, gets out of his green plow truck with a bowling ball bag or something and goes inside. He goes down into the basement of his home and to the gasping surprise of the audience, removes Andera's severed head from his bag. He then places it on the wall next to the heads of various other attractive women in some sick, morbid tableau, a perverted homage to the bedroom wall of his good friend, Paul. " Good night, sweet girl. To all my beautiful girls". He was obviously the small-town "Dexter", no question about it.