Why did RFK takeover the CIA?

RFK was given the assignment by The president JFK because he no longer trusted the leadership of the CIA. They did not accomplish his goal of assassinating Cuban leader Fidel Castro and he thought their was a mole in the CIA because Castro seemed to know exactly when and where the attack on the Island would occur. Some even thought there was more than one mole. President Kennedy also entertained thoughts of dissolving the agency all together. Kennedy was also making plans to withdraw all troops and military advisers from Vietnam. The plans were, according to some, to be finalized after he returned from his trip to Texas.