It's about trying to leave behind the things that you used to love, knowing that you can never have those things again. That nothing will ever quite be the same.
Especially with the lyric "once I've seen the killer up close".
I always took that to mean that the singer saw himself in a mirror, saw that his depression had eaten him away so much that he "killed" his own happiness.
I think the song is about Depression.
It's about trying to leave behind the things that you used to love, knowing that you can never have those things again. That nothing will ever quite be the same.
Especially with the lyric "once I've seen the killer up close".
I always took that to mean that the singer saw himself in a mirror, saw that his depression had eaten him away so much that he "killed" his own happiness.
It's a very deep and sad song.