Lyric discussion by DanL53 

Cover art for Genius lyrics by Warren Zevon

He killed her.

The first two lines are his planning it. The middle of the song is why. By the end he has been arrested and he makes a smart remark about being a genius if he gets his record clean.

And, he will.

This song is exactly why Stephen King once said something to the effect that no music collection is complete without Warren Zevon.