SPOILERS ALERT: Well everyone know now that Ross shot Robert, I did say yesterday that Ross was most likely the shooter, one thing I'm not getting is, why did Ross shot Robert anyway if he knew Andy wasn't gonna shoot Pete in return? I'm thinking it was because he knew that him and Andy have the same issues with their brothers and used that as an excuse to shoot him and flee the village to keep out of sight while the police were around, unless I'm missing something. In my opinion I thought this reveal was a bit of a let down, I mean yeah Ross hasn't got any real motive to really try and kill Robert but it would have been more exciting if it was someone we REALLY wasn't expecting, like Ashley or Paddy.
I've just remembered now that in the end Andy did agree with Ross to shoot Pete but he obviously didn't go through with it and since Ross went away he didn't know that Andy didn't shoot Pete as planned until tonight's episode.
+SilentKiller55 well if you recall Ross dropped the gun at the other side of the fence and had no time to retrieve it, he just assumed Andy would improvise, and he did in a way because Pete almost died with the bike accident but Andy saved him because since Robert wasn't actually dead so in a way nether of them have held there end of the deal.