A killer's note

So far you've done wrong by me
And so I pen this note to thee
I killed once, for reasons just
Now I'm left with horrid lust

I leave a trail of broken men
Alas, my trail will never end
Try to chase me, where I run
But you will never end my fun

I am cunning, I am sly
Do me wrong, and you will die
I killed once for reasons just
I'll kill you too, if I must