That question in science I wish I could give an answer is: Who produced those materials that started the Big Bang in Big Bang theory of the origin of the universe? Alternatively, the question is: How were those materials came about?
I have a Hub on the Big Bang theory and said that that is the mystery in the Big Bang theory of the origin of the universe.
Any answer is improbable to verify. Any answer is neither true nor false as there is no evidence in the long past and in the long future. It belongs in the "law of excluded middle" (Russell, B. Human Knowledge: Its Scope and Limits. 1947).