Random thought: With the Sasuke/Itachi/Kisame encounter that recently occured in the anime, it did come to my mind that if Itachi was indeed blackmailed by Akatsuki, he (on atleast some level) could have been forced into torturing Sasuke since Kisame was standing right there, and as far as Kisame knew, no one was suppost to be living besides Itachi. Afterwards leaving Jiraiya to to force a retreat before Itachi could "finish" with Sasuke. Its possible that Itachi retreated partially because of Sasuke since even Kisame was suprised by the move. Obviously though this is just one giant assumption and shouldn't be taken seriously.