Musically this is OK: it's very John Carpenter - I assume that's deliberate because it's VERY Escape From New York in the intro.
The repeated tag line isn't sinister: repeated so often it becomes silly & then annoying. You might be well served to replace it with something that is less obvious but more sinister.
Something like:
I'm the neighbour,
You wave at me when I mow the lawn,
you came over for a BBQ once,
don't you let your dog crap in my front yard
Have you seen me on the way to work?
It's a blue work van,
the windows are painted white,
I wash out the interior as often as the exterior,
I keep it clean
can I be the clown at your next kiddy party?
It's my side line,
you see
apart from my 9 to 5 job
I'm a serial killer.
Serioulsy though... the music deserves a set of sound bite that build the tension: even chopping up that one phrase so it's
I'm
I'm a
I'm a s
I'm a seer
etc just to bring some matching tension to the words.