Who betrayed Theon Greyjoy?

Who betrayed Theon Greyjoy? Although Theon suggests that Rodrik should be imprisoned, Dagmer insists that Theon must have him executed to maintain the respect of the crew. Rodrik baits Theon into swinging the sword himself and Theon fumbles the task, requiring four blows and a final kick to the neck to sever his head.

Although Theon suggests that Rodrik should be imprisoned, Dagmer insists that Theon must have him executed to maintain the respect of the crew. Rodrik baits Theon into swinging the sword himself and Theon fumbles the task, requiring four blows and a final kick to the neck to sever his head.