The withdrawal of hundreds of corruption charges against Jacob Zuma, immediately prior to his being elected president of South Africa was based on alleged tapes acquired by intelligence officials.  Court rulings demanding that these tapes be handed over to applicants (the DA) have not been complied with on the basis of claims that de Vos argues are legally dubious

http://constitutionallyspeaking.co.za/spy-tapes-a-clear-and-simple-case/