The Koskinen strategy is to:
1) Tell me nothing in e-mails or any other recordable media
2) Keep me in the dark so I can say “I’ve not seen anything...”
3) I will not ask for deeper investigation into anything and you will not suggest.
4) I need to maintain “plausible deniability.”
Tape is cheap and lasts for decades. What good, non criminal reason could there be for not keeping the tapes?