Lyric discussion by Sunny Day Believer 

He was going out with Amy, and killed her. Then he tried to go out with Julie, and killed her.

I think he loved Amy because he killed her, or more precisely, her reaction when he killed her. That's where the line "Julie doesn't scream as well" comes in, because he tried to get that same feeling he got when Amy was screaming by killing Julie, but she didn't do it as well.

He went in and tried to confess to the cops, but they either didn't believe him, or weren't even paying attention.

The last verse of it is him reminiscing on when he killed her, with a full moon out, and she went "violently and quietly" while he sat there and watched her die, they were in a bedroom at the time.

An error occured.