This questions was asked while I was standing in line to pay a bill.
I sketched out the original cover and then it was worked on by designers. They consider your ideas, and familiarize themselves with the story. They then attempt to capture the stories essence with the cover. It evolved from a badge being pierced by an arrow towards wedding rings. The finalized cover involves a fiery arrow with blood splats on the badge. So lets see, we have blood(violence)-badge(police)-on a dark background(sinister intentions).