The letter ***Spoilers
I have 2 questions about Rabbit's father letter to Bob:
-when did Rabbit found it? I guess he didn't start searching the home after he killed Bob... And why would the father choose to write for such a thing, they are apparently living in the same vicinity, why write to his brother? And how did he knew his brother was a serial killer?
-If Bob was asked to kill Rabbit and his mother, why did he keeps him in the end? He says "i didn't ask for you but I will do the better of it" as it it was just fortuitously he was there.