Doubt it was an arkancide, but it would make a good Shakespearean tale. You could have the real father be a mob guy who did the deed and have it be the start of a Macbeth style life. The real father then reappears at key points in young Billy's life, helping him with his political connections in Arkansas and in DC, and giving him his start. Maybe he even learns the ways of the mob under "Dad"'s tutelage, and that experience serves him well when it comes to state troopers, land deals, and the treeatment of witnesses.
I hope you’re writing this all dow....
Oh, silly me! Of course you are!
;-)