Hi. I remember seeing this thriller where this traveling salesman, who has a wife and family back home, picks up this weird guy. He eventually kicks the guy out but the guy continues to stalk him. You also keep hearing about a serial killer on the loose. It turns out that the traveling salesman is the serial killer and he says he kills for “the fun of it.” He then kills the weird guy. The traveling sales man then returns home to his normal life.
This sounds like The Nature Of The Beast (1995): https://en.wikipedia.org/wiki/The_Nature_of_the_Beast
That’s it! Thanks!
Thanks RedScharlach and congrats on your first Solve!