The American lawyer was speaking at an event in London when he said: "The natural next step of the development of an effective ethics process at Fifa is greater transparency.
"The second element that is vital to fulfilling the promise of this reform process is tone at the top.
"More simply put, the second element an institution like Fifa needs in order to meet the challenge of ethics enforcement is leadership. An ethics committee - even a serious, independent ethics committee backed by a strong code of ethics - is not a silver bullet."
