The C.I.A. destroys 'tapes' of interrogations - WHY???

The obvious answer as to why the C.I.A. destroyed the tapes of these interrogations is that they didn't want the information as to procedures, information obtained, who were the interrogators to be 'leaked' to outside sources!!! As to their 'evidence/or being evidentiary of accusations of 'TORTURE' - this is why DEMOCRAT members of CONGRESS and some REPUBLICANS want/demand 'investigations' to the C.I.A.'s actions. FURTHER IT SHOULD BE NOTED THAT THE WHITE HOUSE, THE NSA, THE ATTORNEY-GENERAL AND THEIR VARIOUS LEGAL COUNSELS - ALL ADVISED C.I.A. NOT NOT TO DESTROY THESE TAPES!!! If these tapes had not been destroyed another kerfuffle and endless investigations and posturing for face-time vids could have been avoided!!!