I am - assassin

I killed a man in front of my home yesterday at night
I killed a man and he fell in front of my eyes
My heart stopped in that time
I couldn't breath - I couldn't cry out

I was afraid of my reaction
Run away? Or stay?
I killed a man - it's different
I wouldn't be everything - less assassin

To kill it's worst than to hurt
What would I do?
I couldn't do anything
He passed away and he can't go back

It's only my fault
Oh, God, the fault is mine