The correct answer to this open question is the following.
Although he is not an archeologist, the authority that Semir Osmanagic have to declare this hill a Pyramid is because he has written a book and have talked to many people who knows about pyramids. He has asked permission to enter one of the tunnels of the supposed pyramid complex and has some arguments that support its theory. We have to be very clear on this. It is just a theory that the natural cluster on hills could be in reality the largest pyramid complex on earth.
There is no archeologists that have confirmed his theory. However, we have to say that many people in the metaphysical arena indeed have confirmed what Osmanagic have said, that it is true that the Bosnia complex has three pyramids.